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  • 1.
    Abad, Manuel David
    et al.
    Instituto de Ciencia de Materiales de Sevilla, ICMS (CSIC-US), Spanien.
    Sanjines, Rosendo
    Ecole Polytechnique Federale de Lausanne, IPMC-SB, Lausanne, Schweiz.
    Endrino, Jose Luis
    Instituto de Ciencia de Materiales de Madrid, ICMM (CSIC), Spanien.
    Gago, Raul
    Instituto de Ciencia de Materiales de Madrid, ICMM (CSIC), Spanien.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sanchez-Lopez, Juan Carlos
    Instituto de Ciencia de Materiales de Sevilla, ICMS (CSIC-US), Spanien.
    Identification of Ternary Phases in TiBC/a-C Nanocomposite Thin Films: Influence on the Electrical and Optical Properties2011Ingår i: Plasma Processes and Polymers, ISSN 1612-8850, E-ISSN 1612-8869, Vol. 8, nr 7, s. 579-588Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The local structure of TiBC and amorphous carbon (a-C) nanocomposite films (TiBC/a-C) was correlated with their optical and electrical properties. TiBC/a-C films with increasing C content were deposited by magnetron co-sputtering from TiC:TiB(2) (60: 40) and graphite targets. Chemical composition is determined by electron energy-loss spectroscopy. Grazing incidence X-ray diffraction reveals that the microstructure of the films is amorphous with small nanocrystallites emerging by increasing the C content that could be attributed to the formation of ternary (TiB(x)C(y)) or mixed binary (TiB(2) and TiC) phases. Further information was then obtained by studying the chemical bonding by measuring the near-edge fine structure (NES) by electron energy-loss (B K-, C K-, and Ti L-edges) and X-ray absorption (B K-and Ti L-edges) spectroscopies. The NES analysis indicates the formation of a nanocrystalline ternary TiB(x)C(y) compound concomitant with the segregation of an a-C phase as the carbon content is increased. The optical properties were studied by spectroscopic ellipsometry and the electrical resistivity was measured by the Van der Pauw method between 20 and 300 K. The films continuously lose their metallic character in terms of optical constants and resistivity with increasing carbon content. Theoretical fitting of the electrical properties using the grain-boundary scattering model supported the formation of a nanocomposite structure based on a ternary TiB(x)C(y) phase embedded in a matrix of a-C. The electron transport properties are mainly limited by the high density of point defects, grain size, and transmission probability.

  • 2.
    Abdulahi Mohamed, Abdirahman
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Aksel, Wännström
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Quality Control of Light Emitting Diodes: Using power factor, harmonic distortion and light to power ratios2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This study addresses quality control for Light Emitting Diodes (LED) according to fouraspects, the power factor of LED lamps, their harmonics and total harmonic distortion (THD), the luminosity for total power to radiated power ratio. It focuses on four brands and six different LED lamps, and concludes that IKEA's LED lamps pertain as the quality lamp, with a power factor over 0.9, THD less than 4% and a power to radiated light of over 4%. 

  • 3.
    Abermann, S.
    et al.
    Institute for Solid State Electronics, Vienna University of Technology.
    Efavi, J. K.
    Advanced Microelectronic Center, Aachen.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemme, M. C.
    Advanced Microelectronic Center, Aachen.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E.
    Institute for Solid State Electronics, Vienna University of Technology.
    Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric2007Ingår i: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 84, nr 5-8, s. 1635-1638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We evaluate various metal gate/high-k/Si capacitors by their resulting electrical characteristics. Therefore, we process MOS gate stacks incorporating aluminium (Al), nickel (Ni), titanium-nitride (TiN), and molybdenum (Mo) as the gate material, and metal organic chemical vapour deposited (MOCVD) ZrO2 and HfO2 as the gate dielectric, respectively. The influence of the processing sequence - especially of the thermal annealing treatment - on the electrical characteristics of the various gate stacks is being investigated. Whereas post metallization annealing in forming gas atmosphere improves capacitance-voltage behaviour (due to reduced interface-, and oxide charge density), current-voltage characteristics degrade due to a higher leakage current after thermal treatment at higher temperatures. The Flatband-voltage values for the TiN-, Mo-, and Ni-capacitors indicate mid-gap pinning of the metal gates, however, Ni seems to be thermally unstable on ZrO2, at least within the process scheme we applied.

  • 4. Abermann, S
    et al.
    Efavi, J
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemm, M
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E
    Impact of Al-, Ni-, TiN-, and Mo metal gates on MOCVD-grown HfO2 and ZrO2 high-K dielectrics2006Konferensbidrag (Refereegranskat)
  • 5. Abermann, S.
    et al.
    Efavi, J.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemme, Max
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E.
    Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric2006Ingår i: Presented at Int. Conf. on Micro- and Nano-Engineering, 2006Konferensbidrag (Övrigt vetenskapligt)
  • 6. Abermann, Stephan
    et al.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Efavi, Johnson
    Lemme, Max
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, Emmerich
    Comparative Study On The Impact Of TiN and Mo Metal Gates ON MOCVD-Grown HfO2 and ZrO2 High-k Dielectrics For CMOS Technology2006Ingår i: Proceedings of 28th International Conference on the Physics of Semiconductors (ICPS) / [ed] Wolfgang Jantsch, Friedrich Schäffler, 2006Konferensbidrag (Refereegranskat)
  • 7.
    Aboulfadl, Hisham
    et al.
    Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden.
    Keller, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Larsen, Jes K
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Thuvander, Mattias
    Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden.
    Riekehr, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Platzer Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Microstructural Characterization of Sulfurization Effects in Cu(In,Ga)Se-2 Thin Film Solar Cells2019Ingår i: Microscopy and Microanalysis, ISSN 1431-9276, E-ISSN 1435-8115, Vol. 25, nr 2, s. 532-538Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Surface sulfurization of Cu(In,Ga)Se-2 (CIGSe) absorbers is a commonly applied technique to improve the conversion efficiency of the corresponding solar cells, via increasing the bandgap towards the heterojunction. However, the resulting device performance is understood to be highly dependent on the thermodynamic stability of the chalcogenide structure at the upper region of the absorber. The present investigation provides a high-resolution chemical analysis, using energy dispersive X-ray spectrometry and laser-pulsed atom probe tomography, to determine the sulfur incorporation and chemical re-distribution in the absorber material. The post-sulfurization treatment was performed by exposing the CIGSe surface to elemental sulfur vapor for 20 min at 500 degrees C. Two distinct sulfur-rich phases were found at the surface of the absorber exhibiting a layered structure showing In-rich and Ga-rich zones, respectively. Furthermore, sulfur atoms were found to segregate at the absorber grain boundaries showing concentrations up to similar to 7 at% with traces of diffusion outwards into the grain interior.

  • 8.
    Abou-Ras, Daniel
    et al.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Wagner, Sigurd
    Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA..
    Stanbery, Bill J.
    Siva Power, 5102 Calle Sol, Santa Clara, CA 95054 USA..
    Schock, Hans-Werner
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Scheer, Roland
    Martin Luther Univ Halle Wittenberg, Inst Phys, Photovolta Grp, D-06120 Halle, Saale, Germany..
    Stolt, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Solibro Res AB, Sweden.
    Siebentritt, Susanne
    Univ Luxembourg, Phys & Mat Sci Res Unit, Lab Photovolta, Belvaux, Luxembourg..
    Lincot, Daniel
    CNRS EDF Chim Paristech PSL, Inst Photovolta Ile France IPVF, IRDEP, 6 Quai Watier, F-78401 Chatou, France..
    Eberspacher, Chris
    Solopower Syst Inc, Corp & Mfg Headquarters, 6308 North Marine Dr, Portland, OR 97203 USA..
    Kushiya, Katsumi
    Solar Frontier KK, 123-1 Shimo Kawairi, Atsugi, Kanagawa, Japan..
    Tiwari, Ayodhya N.
    Empa Swiss Fed Labs Mat Sci & Technol, Lab Thin Films & Photovolta, Ueberlandstr 129, CH-8600 Dubendorf, Switzerland..
    Innovation highway: Breakthrough milestones and key developments in chalcopyrite photovoltaics from a retrospective viewpoint2017Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 633, s. 2-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present contribution is a summary of an event that was organized as a special evening session in Symposium V "Chalcogenide Thin-Film Solar Cells" at the E-MRS 2016 Spring Meeting, Lille, France. The presentations in this session were given by the coauthors of this paper. These authors present retrospectives of key developments in the field of Cu(In,Ga)(S,Se)(2) solar cells as they themselves had witnessed in their laboratories or companies. Also, anecdotes are brought up, which captured interesting circumstances in that evolutionary phase of the field. Because the focus was on historical perspectives rather than a comprehensive review of the field, recent developments intentionally were not addressed.

  • 9.
    Abro, Mehwish
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Modelling the exfoliation of graphite for production of graphene2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aim of my thesis is to make a theoretical model of data obtained from liquid-phase exfoliation of graphene. The production of graphene in the liquid phase exfoliation is a cost efficient method One part of this work is devotedto learn the method of production of graphene by the shear mixing technique from the graphite and to estimate some important parameters which are crucial for the process. Other part of my work is based on studying the liquid-phase exfoliation mechanism of graphene through ultrasonication technique. This method is time consuming as compared to shearmixing.

  • 10.
    Adolfsson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Characterization of combinatorial Cu2ZnSnS4 thin films2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The kesterite Cu2ZnSnS4 (CZTS) is considered as a possible absorber layer in future photovoltaic (PV) applications. The abundance of its constituent elements along with the material being non-toxic and having a direct band gap of around 1.5 eV make it an attractive material for solar cell applications. So far, cells with an efficiency of 12.6 % have been achieved. The limiting factor is the finished cells' open circuit voltage (VOC) deficit which has been attributed to structural defects in the material. Problems with sustaining a sulfur-enriched atmosphere during the annealing step of material production have been observed, and are thought to be partially responsible for the high density of structural defects. Elemental sulfur is commonly used for inducing a sulfur-enriched atmosphere in the anneal. In this study, four combinatorial and polycrystalline CZTS thin films were prepared and annealed in different conditions with regards to time, sulfur source and amount. The samples were characterized using energy dispersive-, Raman- and photoluminescence spectroscopy. The effect of the anneal on the different composition regions were analyzed and secondary phases were identified. Introducing CuS as the sulfur source during the anneal reduced the decomposition of the CZTS phase, and lowered the density of the defect complex [ZnCu + CuZn], while enlarging the single phase region. Strictly and highly Sn-rich compositions of CZTS was observed to yield both high cation order and photoluminescence intensity, and a link between the two parameters was observed.

  • 11.
    Ahlberg, Patrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Graphene Implementation Study in Semiconductor Processing2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Graphene, with its two-dimensional nature and unique properties, has for over a decade captured enormous interests in both industry and academia. This work tries to answer the question of what would happen to graphene when it is subjected to various processing conditions and how this would affect the graphene functionality. The focus is placed on its ability to withstand different thin-film deposition environments with regard to the implementation of graphene in two application areas: as a diffusion barrier and in electronic devices.

    With single-layer graphene films grown in-house by means of chemical vapor deposition (CVD), four techniques among the well-established thin-film deposition methods are studied in detail: atomic layer deposition (ALD), evaporation, sputter-deposition and spray-deposition. And in this order, these methods span a large range of kinetic impact energies from low to high. Graphene is known to have a threshold displacement energy of 22 eV above which carbon atoms are ejected from the lattice. Thus, ALD and evaporation work with energies below this threshold, while sputtering and spraying may involve energies above. The quality of the graphene films undergone the various depositions is mainly evaluated using Raman spectroscopy.

    Spray deposition of liquid alloy Ga-In-Sn is shown to require a stack of at least 4 layers of graphene in order to act as an effective barrier to the Ga diffusion after the harsh spray-processing. Sputter-deposition is found to benefit from low substrate temperature and high chamber pressure (thereby low kinetic impact energy) so as to avoid damaging the graphene. Reactive sputtering should be avoided. Evaporation is non-invasiveness with low kinetic impact energy and graphene can be subjected to repeated evaporation and removal steps without losing its integrity. With ALD, the effects on graphene are of different nature and they are investigated in the field-effect-transistor (FET) configuration. The ALD process for deposition of Al2O3 films is found to remove undesired dopants from the prior processing and the Al2O3 films are shown to protect the graphene channel from doping by oxygen. When the substrate is turned hydrophobic by chemical treatment prior to graphene transfer-deposition, a unipolar transistor behavior is obtained.

    Delarbeten
    1. A two-in-one process for reliable graphene transistors processed with photolithography
    Öppna denna publikation i ny flik eller fönster >>A two-in-one process for reliable graphene transistors processed with photolithography
    Visa övriga...
    2015 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, nr 20, artikel-id 203104Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Research on graphene field-effect transistors (GFETs) has mainly relied on devices fabricated using electron-beam lithography for pattern generation, a method that has known problems with polymer contaminants. GFETs fabricated via photo-lithography suffer even worse from other chemical contaminations, which may lead to strong unintentional doping of the graphene. In this letter, we report on a scalable fabrication process for reliable GFETs based on ordinary photo-lithography by eliminating the aforementioned issues. The key to making this GFET processing compatible with silicon technology lies in a two-in-one process where a gate dielectric is deposited by means of atomic layer deposition. During this deposition step, contaminants, likely unintentionally introduced during the graphene transfer and patterning, are effectively removed. The resulting GFETs exhibit current-voltage characteristics representative to that of intrinsic non-doped graphene. Fundamental aspects pertaining to the surface engineering employed in this work are investigated in the light of chemical analysis in combination with electrical characterization.

    Nationell ämneskategori
    Fysik Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-269191 (URN)10.1063/1.4935985 (DOI)000365688700049 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0113, 2011.0082Stiftelsen för strategisk forskning (SSF), SE13-0061Vetenskapsrådet, 621-2014-5591
    Tillgänglig från: 2015-12-14 Skapad: 2015-12-14 Senast uppdaterad: 2017-12-01Bibliografiskt granskad
    2. Interface Dependent Effective Mobility in Graphene Field Effect Transistors
    Öppna denna publikation i ny flik eller fönster >>Interface Dependent Effective Mobility in Graphene Field Effect Transistors
    2018 (Engelska)Ingår i: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, nr 3, s. 1757-1761Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.

    Nationell ämneskategori
    Teknik och teknologier Elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-284924 (URN)10.1007/s11664-017-6023-6 (DOI)000424341700002 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0082Vetenskapsrådet, 2014-5591
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2018-04-11Bibliografiskt granskad
    3. Defect formation in graphene during low-energy ion bombardment
    Öppna denna publikation i ny flik eller fönster >>Defect formation in graphene during low-energy ion bombardment
    Visa övriga...
    2016 (Engelska)Ingår i: APL Materials, ISSN 2166-532X, Vol. 4, nr 4, artikel-id 046104Artikel i tidskrift, Letter (Refereegranskat) Published
    Abstract [en]

    This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar+ ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV's up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.

    Nationell ämneskategori
    Materialkemi Nanoteknik
    Identifikatorer
    urn:nbn:se:uu:diva-284702 (URN)10.1063/1.4945587 (DOI)000375846100007 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0082Vetenskapsrådet, 2014-5591 2014-6463
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2017-01-25Bibliografiskt granskad
    4. Toward synthesis of oxide films on graphene with sputtering based processes
    Öppna denna publikation i ny flik eller fönster >>Toward synthesis of oxide films on graphene with sputtering based processes
    2016 (Engelska)Ingår i: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-284706 (URN)
    Externt samarbete:
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2017-11-30
    5. Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts
    Öppna denna publikation i ny flik eller fönster >>Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts
    Visa övriga...
    2014 (Engelska)Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 61, nr 8, s. 2996-3000Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This paper presents the use of graphene as a diffusion barrier to a eutectic Ga-In-Sn alloy, i.e., galinstan, for electrical contacts in electronics. Galinstan is known to be incompatible with many conventional metals used for electrical contacts. When galinstan is in direct contact with Al thin films, Al is readily dissolved leading to the formation of Al oxides present on the surface of the galinstan droplets. This reaction is monitored ex situ using several material analysis methods as well as in situ using a simple circuit to follow the time-dependent resistance variation. In the presence of a multilayer graphene diffusion barrier, the Al-galinstan reaction is effectively prevented for galinstan deposited by means of drop casting. When deposited by spray coating, the high-impact momentum of the galinstan droplets causes damage to the multilayer graphene and the Al-galinstan reaction is observed at some defective spots. Nonetheless, the graphene barrier is likely to block the formation of Al oxides at the Al/galinstan interface leading to a stable electrical current in the test circuit.

    Nationell ämneskategori
    Annan elektroteknik och elektronik Nanoteknik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik; Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-229503 (URN)10.1109/TED.2014.2331893 (DOI)000342906200056 ()
    Tillgänglig från: 2014-08-10 Skapad: 2014-08-10 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    6. Scalable residue-free graphene for surface-enhanced Raman scattering
    Öppna denna publikation i ny flik eller fönster >>Scalable residue-free graphene for surface-enhanced Raman scattering
    Visa övriga...
    2016 (Engelska)Ingår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 98, s. 567-571Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A room-temperature polymer-assisted transfer process is developed for large-area, single-layer graphene grown by means of chemical vapor deposition (CVD). This process leads to transferred graphene layers free of polymer contamination. The absence of polymer residues boosts the surface-enhanced Raman scattering (SERS) of the CVD graphene with gold nanoparticles (Au NPs) deposited atop by evaporation. The SERS enhancement of the CVD graphene reaches similar to 120 for the characteristic 2D peak of graphene, the highest enhancement factor achieved to date, when the Au NPs are at the threshold of percolation. Our simulation supported by experiment suggests that the polymer residues persistently present on the graphene transferred by the conventional polymer-assisted method are equivalent to an ultrathin film of less than 1 nm thickness. The presence of polymer residues drastically reduces SERS due to the separation of the Au NPs from the underlying graphene. The scalability of CVD graphene opens up for the possibility of graphene-based SERS sensors.

    Nationell ämneskategori
    Fysik Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-269192 (URN)10.1016/j.carbon.2015.11.043 (DOI)000367233000070 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0113Knut och Alice Wallenbergs Stiftelse, 2011.0082Stiftelsen för strategisk forskning (SSF), SE13-0061Vetenskapsrådet, 621-2014-5591
    Tillgänglig från: 2015-12-14 Skapad: 2015-12-14 Senast uppdaterad: 2017-12-01Bibliografiskt granskad
  • 12.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Hinnemo, Malkolm
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Song, Man
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Gao, Xindong
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhi-Bin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    A two-in-one process for reliable graphene transistors processed with photolithography2015Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, nr 20, artikel-id 203104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research on graphene field-effect transistors (GFETs) has mainly relied on devices fabricated using electron-beam lithography for pattern generation, a method that has known problems with polymer contaminants. GFETs fabricated via photo-lithography suffer even worse from other chemical contaminations, which may lead to strong unintentional doping of the graphene. In this letter, we report on a scalable fabrication process for reliable GFETs based on ordinary photo-lithography by eliminating the aforementioned issues. The key to making this GFET processing compatible with silicon technology lies in a two-in-one process where a gate dielectric is deposited by means of atomic layer deposition. During this deposition step, contaminants, likely unintentionally introduced during the graphene transfer and patterning, are effectively removed. The resulting GFETs exhibit current-voltage characteristics representative to that of intrinsic non-doped graphene. Fundamental aspects pertaining to the surface engineering employed in this work are investigated in the light of chemical analysis in combination with electrical characterization.

  • 13.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Hinnemo, Malkolm
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Interface Dependent Effective Mobility in Graphene Field Effect Transistors2018Ingår i: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, nr 3, s. 1757-1761Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.

  • 14.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Johansson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Zhang, Zhibin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jansson, Ulf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lindblad, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Nyberg, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Defect formation in graphene during low-energy ion bombardment2016Ingår i: APL Materials, ISSN 2166-532X, Vol. 4, nr 4, artikel-id 046104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar+ ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV's up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.

  • 15.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhibin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Toward synthesis of oxide films on graphene with sputtering based processes2016Ingår i: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754Artikel i tidskrift (Refereegranskat)
  • 16.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Nyberg, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhi-Bin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jansson, Ulf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Toward synthesis of oxide films on graphene with sputtering based processes2016Ingår i: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 34, nr 4, artikel-id 040605Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The impact of energetic particles associated with a sputter deposition process may introduce damage to single layer graphene films, making it challenging to apply this method when processing graphene. The challenge is even greater when oxygen is incorporated into the sputtering process as graphene can be readily oxidized. This work demonstrates a method of synthesizing ZnSn oxide on graphene without introducing an appreciable amount of defects into the underlying graphene. Moreover, the method is general and applicable to other oxides. The formation of ZnSn oxide is realized by sputter deposition of ZnSn followed by a postoxidation step. In order to prevent the underlying graphene from damage during the initial sputter deposition process, the substrate temperature is kept close to room temperature, and the processing pressure is kept high enough to effectively suppress energetic bombardment. Further, in the subsequent postannealing step, it is important not to exceed temperatures resulting in oxidation of the graphene. The authors conclude that postoxidation of ZnSn is satisfactorily performed at 300 degrees C in pure oxygen at reduced pressure. This process results in an oxidized ZnSn film while retaining the initial quality of the graphene film.

  • 17.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Seung, Hee Jeong
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jiao, Mingzhi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Wu, Zhigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhi-Bin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts2014Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 61, nr 8, s. 2996-3000Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the use of graphene as a diffusion barrier to a eutectic Ga-In-Sn alloy, i.e., galinstan, for electrical contacts in electronics. Galinstan is known to be incompatible with many conventional metals used for electrical contacts. When galinstan is in direct contact with Al thin films, Al is readily dissolved leading to the formation of Al oxides present on the surface of the galinstan droplets. This reaction is monitored ex situ using several material analysis methods as well as in situ using a simple circuit to follow the time-dependent resistance variation. In the presence of a multilayer graphene diffusion barrier, the Al-galinstan reaction is effectively prevented for galinstan deposited by means of drop casting. When deposited by spray coating, the high-impact momentum of the galinstan droplets causes damage to the multilayer graphene and the Al-galinstan reaction is observed at some defective spots. Nonetheless, the graphene barrier is likely to block the formation of Al oxides at the Al/galinstan interface leading to a stable electrical current in the test circuit.

  • 18. Ahlén, I
    et al.
    Pettersson, L
    Svärdström, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    An instrument for detecting bat and insect sounds1983Ingår i: Myotis, Vol. 21-22, s. 82-88Artikel i tidskrift (Refereegranskat)
  • 19.
    Ahvenniemi, Esko
    et al.
    Aalto Univ, Dept Chem, POB 16100, FI-00076 Espoo, Finland..
    Akbashev, Andrew R.
    Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA..
    Ali, Saima
    Aalto Univ, Sch Chem Technol, Dept Mat Sci & Engn, POB 16200, FI-00076 Aalto, Finland..
    Bechelany, Mikhael
    Univ Montpellier, ENSCM, CNRS, IEM,UMR 5635, Pl Eugene Bataillon, F-34095 Montpellier 5, France..
    Berdova, Maria
    Univ Twente, Ind Focus Grp XUV Opt, NL-7522 ND Enschede, Netherlands..
    Boyadjiev, Stefan
    Bulgarian Acad Sci, Inst Solid State Phys, 72 Tzarigradsko Chaussee Blvd, Sofia 1784, Bulgaria..
    Cameron, David C.
    Masaryk Univ, CEPLANT, Kotlarska 267-2, CS-61137 Brno, Czech Republic..
    Chen, Rong
    Huazhong Univ Sci & Technol, Sch Mech Sci & Engn, Sch Opt & Elect Informat, 1037 Luoyu Rd, Wuhan 430074, Hubei, Peoples R China..
    Chubarov, Mikhail
    Univ Grenoble Alpes, CNRS, SIMAP, F-38000 Grenoble, France..
    Cremers, Veronique
    Univ Ghent, CoCooN, Dept Solid State Sci, Krijgslaan 281-S1, B-9000 Ghent, Belgium..
    Devi, Anjana
    Ruhr Univ Bochum, Inorgan Mat Chem, D-44801 Bochum, Germany..
    Drozd, Viktor
    St Petersburg State Univ, Inst Chem, Univ Skaya Emb 7-9, St Petersburg 199034, Russia..
    Elnikova, Liliya
    Inst Theoret & Expt Phys, Bolshaya Cheremushkinskaya 25, Moscow 117218, Russia..
    Gottardi, Gloria
    Fdn Bruno Kessler, Ctr Mat & Microsyst, I-38123 Trento, Italy..
    Grigoras, Kestutis
    VTT Tech Res Ctr Finland, POB 1000,Tietotie 3, FI-02044 Espoo, Vtt, Finland..
    Hausmann, Dennis M.
    Lam Res Corp, Tualatin, OR 97062 USA..
    Hwang, Cheol Seong
    Seoul Natl Univ, Dept Mat Sci & Engn, Coll Engn, Seoul 08826, South Korea.;Seoul Natl Univ, Interuniv Semicond Res Ctr, Coll Engn, Seoul 08826, South Korea..
    Jen, Shih-Hui
    Globalfoundries, Albany, NY 12203 USA..
    Kallio, Tanja
    Aalto Univ, Sch Chem Engn, Dept Chem, POB 16100, FI-00076 Aalto, Finland..
    Kanervo, Jaana
    Aalto Univ, Sch Chem Engn, Dept Chem, POB 16100, FI-00076 Aalto, Finland.;Abo Akad Univ, FI-20500 Turku, Finland..
    Khmelnitskiy, Ivan
    St Petersburg Electrotech Univ LETI, Res & Educ Ctr Nanotechnol, Ul Prof Popova 5, St Petersburg 197376, Russia..
    Kim, Do Han
    MIT, Dept Chem Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA..
    Klibanov, Lev
    Techinsights, 3000 Solandt Rd, Ottawa, ON K2K2X2, Canada..
    Koshtyal, Yury
    Ioffe Inst, Lab Lithium Ion Technol, 26 Politekhnicheskaya, St Petersburg 194021, Russia..
    Krause, A. Outi I.
    Aalto Univ, Sch Chem Technol, Dept Mat Sci & Engn, POB 16200, FI-00076 Aalto, Finland..
    Kuhs, Jakob
    Univ Ghent, CoCooN, Dept Solid State Sci, Krijgslaan 281-S1, B-9000 Ghent, Belgium..
    Kaerkkaenen, Irina
    Sentech Instruments GmbH, Schwarzschildstr 2, D-12489 Berlin, Germany..
    Kaariainen, Marja-Leena
    NovaldMed Ltd Oy, Telkantie 5, FI-82500 Kitee, Finland..
    Kaariainen, Tommi
    NovaldMed Ltd Oy, Telkantie 5, FI-82500 Kitee, Finland.;Univ Helsinki, Inorgan Chem Lab, POB 55,AI Virtasen Aukio 1, FI-00014 Helsinki, Finland..
    Lamagna, Luca
    STMicroelectronics, Via C Olivetti 2, I-20864 Agrate Brianza, MB, Italy..
    Lapicki, Adam A.
    Seagate Technol Ireland, 1 Disc Dr, Derry BT48 7BD, North Ireland..
    Leskela, Markku
    Univ Helsinki, Dept Chem, POB 55, FI-00014 Helsinki, Finland..
    Lipsanen, Harri
    Aalto Univ, Dept Micro & Nanosci, Tietotie 3, Espoo 02150, Finland..
    Lyytinen, Jussi
    Aalto Univ, Sch Chem Technol, Dept Mat Sci & Engn, POB 16200, FI-00076 Aalto, Finland..
    Malkov, Anatoly
    Tech Univ, St Petersburg State Inst Technol, Dept Chem Nanotechnol & Mat Elect, 26 Moskovsky Prosp, St Petersburg 190013, Russia..
    Malygin, Anatoly
    Tech Univ, St Petersburg State Inst Technol, Dept Chem Nanotechnol & Mat Elect, 26 Moskovsky Prosp, St Petersburg 190013, Russia..
    Mennad, Abdelkader
    CDER, UDES, RN 11 BP 386 Bou Ismail, Tipasa 42415, Algeria..
    Militzer, Christian
    Tech Univ Chemnitz, Inst Chem, Phys Chem, Str Nationen 62, D-09111 Chemnitz, Germany..
    Molarius, Jyrki
    Summa Semicond Oy, PL 11, Espoo 02131, Finland..
    Norek, Malgorzata
    Mil Univ Technol, Fac Adv Technol & Chem, Dept Adv Mat & Technol, Str Kaliskiego 2, PL-00908 Warsaw, Poland..
    Ozgit-Akgun, Cagla
    ASELSAN Inc, Microelect Guidance & Electroopt Business Sect, TR-06750 Ankara, Turkey..
    Panov, Mikhail
    St Petersburg Electrotech Univ LETI, Ctr Microtechnol & Diagnost, Ul Prof Popova 5, St Petersburg 197376, Russia..
    Pedersen, Henrik
    Linkoping Univ, Dept Phys Chem & Biol, SE-58183 Linkoping, Sweden..
    Piallat, Fabien
    KOBUS, F-38330 Montbonnot St Martin, France..
    Popov, Georgi
    Univ Helsinki, Dept Chem, POB 55, FI-00014 Helsinki, Finland..
    Puurunen, Riikka L.
    VTT Tech Res Ctr Finland, POB 1000,Tietotie 3, FI-02044 Espoo, Vtt, Finland..
    Rampelberg, Geert
    Univ Ghent, CoCooN, Dept Solid State Sci, Krijgslaan 281-S1, B-9000 Ghent, Belgium..
    Ras, Robin H. A.
    Rauwel, Erwan
    Tallinn Univ Technol, Tartu Coll, Puiestee 78, EE-51008 Tartu, Estonia..
    Roozeboom, Fred
    Eindhoven Univ Technol, Dept Appl Phys, Grp Plasma & Mat Proc, POB 513, NL-5600 MB Eindhoven, Netherlands.;TNO, High Tech Campus 21, NL-5656 AE Eindhoven, Netherlands..
    Sajavaara, Timo
    Univ Jyvaskyla, Dept Phys, POB 35, Jyvaskyla 40014, Finland..
    Salami, Hossein
    Univ Maryland, Dept Chem & Biomol Engn, College Pk, MD 20742 USA..
    Savin, Hele
    Aalto Univ, Dept Micro & Nanosci, Tietotie 3, Espoo 02150, Finland..
    Schneider, Nathanaelle
    IRDEP CNRS, 6 Quai Watier, F-78401 Chatou, France.;IPVF, 8 Rue Renaissance, F-92160 Antony, France..
    Seidel, Thomas E.
    Seitek50, POB 350238, Palm Coast, FL 32135 USA..
    Sundqvist, Jonas
    Fraunhofer Inst Ceram Technol & Syst IKTS, Syst Integrat & Technol Transfer, Winterbergstr 28, D-01277 Dresden, Germany..
    Suyatin, Dmitry B.
    Lund Univ, Div Solid State Phys, Box 118, SE-22100 Lund, Sweden.;Lund Univ, NanoLund, Box 118, SE-22100 Lund, Sweden..
    Törndahl, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    van Ommen, J. Ruud
    Delft Univ Technol, Dept Chem Engn, Van der Maasweg 9, NL-2629 HZ Delft, Netherlands..
    Wiemer, Claudia
    CNR, IMM, Lab MDM, Via C Olivetti 2, I-20864 Agrate Brianza, MB, Italy..
    Ylivaara, Oili M. E.
    VTT Tech Res Ctr Finland, POB 1000,Tietotie 3, FI-02044 Espoo, Vtt, Finland..
    Yurkevich, Oksana
    Immanuel Kant Balt Fed Univ, Res & Educ Ctr Funct Nanomat, A Nevskogo 14, Kaliningrad 236041, Russia..
    Recommended reading list of early publications on atomic layer deposition-Outcome of the "Virtual Project on the History of ALD"2017Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 35, nr 1, artikel-id 010801Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency.

  • 20.
    Aiempanakit, M
    et al.
    Plasma & Coatings Physics Division, IFM-Material Physics, Linköpings universitet.
    Aijaz, A
    Plasma & Coatings Physics Division, IFM-Material Physics, Linköpings universitet.
    Lundin, D
    Plasma & Coatings Physics Division, IFM-Material Physics, Linköpings universitet.
    Helmersson, U
    Plasma & Coatings Physics Division, IFM-Material Physics, Linköpings universitet.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Understanding the discharge current behavior in reactive high power impulse magnetron sputtering of oxides2012Konferensbidrag (Refereegranskat)
  • 21. Aiempanakit, Montri
    et al.
    Aijaz, Asim
    Lundin, Daniel
    Helmersson, Ulf
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Understanding the discharge current behavior in reactive high power impulse magnetron sputtering of oxides2013Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 13, s. 133302-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The discharge current behavior in reactive high power impulse magnetron sputtering (HiPIMS) of Ti-O and Al-O is investigated. It is found that for both metals, the discharge peak current significantly increases in the oxide mode in contrast to the behavior in reactive direct current magnetron sputtering where the discharge current increases for Al but decreases for Ti when oxygen is introduced. In order to investigate the increase in the discharge current in HiPIMS-mode, the ionic contribution of the discharge in the oxide and metal mode is measured using time-resolved mass spectrometry. The energy distributions and time evolution are investigated during the pulse-on time as well as in the post-discharge. In the oxide mode, the discharge is dominated by ionized oxygen, which has been preferentially sputtered from the target surface. The ionized oxygen determines the discharge behavior in reactive HiPIMS.

  • 22.
    Aiempanakit, Montri
    et al.
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Helmersson, Ulf
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Aijaz, Asim
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Larsson, Petter
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Magnusson, Roger
    Laboratory of Applied Optics, Linköping University.
    Jensen, Jens
    Thin Film Physics Division, IFM, Materials Physics, Linköping University.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Effect of peak power in reactive high power impulse magnetron sputtering of titanium dioxide2011Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 205, nr 20, s. 4828-4831Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of peak power in a high power impulse magnetron sputtering (HiPIMS) reactive deposition of TiO(2) films has been studied with respect to the deposition rate and coating properties. With increasing peak power not only the ionization of the sputtered material increases but also their energy. In order to correlate the variation in the ion energy distributions with the film properties, the phase composition, density and optical properties of the films grown with different HiPIMS-parameters have been investigated and compared to a film grown using direct current magnetron sputtering (DCMS). All experiments were performed for constant average power and pulse on time (100W and 35 mu s, respectively), different peak powers were achieved by varying the frequency of pulsing. Ion energy distributions for Ti and O and its dependence on the process conditions have been studied. It was found that films with the highest density and highest refractive index were grown under moderate HiPIMS conditions (moderate peak powers) resulting in only a small loss in mass-deposition rate compared to DCMS. It was further found that TiO2 films with anatase and rutile phases can be grown at room temperature without substrate heating and without post-deposition annealing.

  • 23.
    Aiempanakit, Montri
    et al.
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Larsson, Petter
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Sarakinos, Kostas
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Jensen, Jens
    Thin Film Physics Division , IFM, Material Physics, Linköping University.
    Helmersson, Ulf
    Plasma & Coatings Physics Division, IFM, Material Physics, Linköping University.
    Hysteresis and process stability in reactive high power impulse magnetron sputtering of metal oxides2011Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 22, s. 7779-7784Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the further development of reactive sputter deposition, strategies which allow for stabilization of the transition zone between the metallic and compound modes, elimination of the process hysteresis, and increase of the deposition rate, are of particular interest. In this study, the hysteresis behavior and the characteristics of the transition zone during reactive high power impulse magnetron sputtering (HiPIMS) of Al and Ce targets in an Ar-O(2) atmosphere as a function of the pulsing frequency and the pumping speed are investigated. Comparison with reactive direct current magnetron sputtering (DCMS) reveals that HiPIMS allows for elimination/suppression of the hysteresis and a smoother transition from the metallic to the compound sputtering mode. For the experimental conditions employed in the present study, optimum behavior with respect to the hysteresis width is obtained at frequency values between 2 and 4 kHz, while HiPIMS processes with values below or above this range resemble the DCMS behavior. Al-O films are deposited using both HiPIMS and DCMS. Analysis of the film properties shows that elimination/suppression of the hysteresis in HiPIMS facilitates the growth of stoichiometric and transparent Al(2)O(3) at relatively high deposition rates over a wider range of experimental conditions as compared to DCMS.

  • 24.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Carreri, Felipe de Campos
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Sabelfeld, Alex
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Gerdes, Holger
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Bandorf, Ralf
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bräuer, Günter
    Fraunhofer Institute for Surface Engineering and Thin Films, IST, Braunschweig, Germany.
    Industrial Scale Deposition of Diamond-like Carbon Thin Films using Ne-based HiPIMS Discharge2015Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) has been successful in providing highly ionized deposition fluxes for most common metals (Cu, Al, Ti). However, it is challenged when non-metals such as carbon is considered. Highly ionized carbon fluxes (up to 100%) are essential for the synthesis of diamond-like carbon and tetrahedral amorphous carbon thin films. Earlier reports have shown that the C+/C0 ratio in HiPIMS does not exceed 5% and film densities and sp3/sp2 bond fractions are substantially lower than those achieved using ionized physical vapour deposition based methods such as filtered cathodic vacuum arc and pulsed laser deposition. In our previous work, we demonstrated that Ne-based HiPIMS discharge entails energetic electrons as compared to Ar-based HiPIMS discharge facilitating the generation of highly ionized C fluxes as well as diamond-like carbon thin films with mass densities in the order of 2.8 g/cm3

    In this work, we perform industrial scale deposition of diamond-like carbon thin films using Ne- as well as Ar-based HiPIMS discharge. In order to investigate the effect of electron temperature enhancement and its correlation to generation of C1+ ion fluxes in Ne-based HiPIMS discharge, we perform time-averaged and time-resolved measurements of electron temperature as well as ion density at the substrate position using a flat probe. We also investigate the effect of plasma properties on the ionization of sputtered C as well as buffer gas species by measuring the optical emission from the discharge. In order to correlate the plasma and film properties, we synthesize C thin films under energetic deposition conditions and investigate structural (mass density, sp3/sp2 bond fraction, H content) and mechanical (hardness, elastic modulus, adhesion strength) properties of the resulting diamond-like carbon thin films.

  • 25.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ferreira, Fabio
    Univ Coimbra, SEG CEMMPRE Dept Mech Engn, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal.
    Oliveira, Joao
    Univ Coimbra, SEG CEMMPRE Dept Mech Engn, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Mechanical Properties of Hydrogen Free Diamond-Like Carbon Thin Films Deposited by High Power Impulse Magnetron Sputtering with Ne2018Ingår i: Coatings, ISSN 2079-6412, Vol. 8, nr 11, artikel-id 385Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrogen-free diamond-like carbon (DLC) thin films are attractive for a wide range of industrial applications. One of the challenges related to the use of hard DLC lies in the high intrinsic compressive stresses that limit the film adhesion. Here, we report on the mechanical and tribological properties of DLC films deposited by High Power Impulse Magnetron Sputtering (HiPIMS) with Ne as the process gas. In contrast to standard magnetron sputtering as well as standard Ar-based HiPIMS process, the Ne-HiPIMS lead to dense DLC films with increased mass density (up to 2.65 g/cm(3)) and a hardness of 23 GPa when deposited on steel with a Cr + CrN adhesion interlayer. Tribological testing by the pin-on-disk method revealed a friction coefficient of 0.22 against steel and a wear rate of 2 x 10(-17) m(3)/Nm. The wear rate is about an order of magnitude lower than that of the films deposited using Ar. The differences in the film properties are attributed to an enhanced C ionization in the Ne-HiPIMS discharge.

  • 26.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomás
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Low-temperature synthesis of thermochromic vanadium dioxide thin films using reactive magnetron sputtering2015Ingår i: Abstracts, 2015Konferensbidrag (Refereegranskat)
  • 27.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Montero, Jose
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomáš
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Deposition of thermochromic vanadium dioxide thin films by reactive high power impulse magnetron sputtering2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Vanadium dioxide exhibits a reversible phase transition from semiconducting state (monoclinic structure) to a metallic state (tetragonal structure) at ~68 oC. This so-called metal-insulator transition (MIT) entails thermochromic behavior manifested by large changes in optical properties, such as high infrared transmittance modulation in thin films, thereby making VO2-based films a suitable candidate for optical switching applications such as self-tunable infrared filters. Thermochromic VO2 thin films have been widely investigated for optical applications, but high growth temperatures (> 400 oC) required for synthesizing crystalline VO2 thin films, high MIT temperature (68 oC) as well as low visible transmittance (typically ~50%) limit their applicability for example for energy efficient smart windows.

     

    Synthesis of metal-oxide thin films using highly ionized vapor fluxes has been shown to facilitate low-temperature film growth as well as control over phase formation and resulting film properties. In the present work, we synthesize VO2 thin films by use of highly ionized vapor fluxes that are generated by high power impulse magnetron sputtering (HiPIMS). In order to establish a correlation between the plasma and film properties, we investigate the discharge characteristics by analyzing the discharge current-voltage characteristics under varied process parameters such as peak-power, pulse-width and gas phase composition and grow VO2 thin films under suitable process conditions. We investigate the effect of growth temperature (room temperature to 500 oC), energy of the deposition flux (controlled by substrate bias potential) and type of substrate (Si, glass, ITO-coated glass) on crystallinity, phase formation and on optical properties (visible transmittance and infrared modulation) of the resulting thin films. For reference, the discharge characteristics and properties of films deposited by pulsed direct current magnetron sputtering are also studied.         

  • 28.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ji, Yu-Xia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Montero, Jose
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Low-temperature synthesis of thermochromic vanadium dioxide thin films by reactive high power impulse magnetron sputtering2016Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 149, s. 137-144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermochromic (TC) vanadium dioxide thin films provide means for controlling solar energy throughput and can be used for energy-saving applications such as smart windows. One of the factors limiting the deployment of VO2 films in TC devices is the growth temperature tau(s). At present, temperatures in excess of 450 degrees C are required, which clearly can be an impediment especially for temperature-sensitive substrates. Here we address the issue of high tau(s) by synthesizing VO2 thin films from highly ionized fluxes of depositing species generated in high power impulse magnetron sputtering (HiPIMS) discharges. The use of ions facilitates low-temperature film growth because the energy of the depositing species can be readily manipulated by substrate bias. For comparison, films were also synthesized by pulsed direct current magnetron sputtering. Structural and optical characterization of VO2 thin films on ITO-coated glass substrates confirms previous results that HiPIMS allows tau(s) to be reduced from 500 to 300 degrees C. Importantly, we demonstrated that HiPIMS permits the composition and TC response of the films to be tuned by altering the energy of the deposition flux via substrate bias. An optimum ion energy of 100 eV was identified, which points at a potential for further reduction of tau(s) thereby opening new possibilities for industrially-relevant applications of VO2-based TC thin films. Weak TC activity was observed even at tau(s) approximate to 200 degrees C in HiPIMS-produced films.

  • 29.
    Aijaz, Asim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ion induced stress relaxation in dense sputter-deposited DLC thin films2017Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, nr 5, artikel-id 051902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deposition of high-density and low-stress hydrogen-free diamond like carbon (DLC) thin films is demonstrated using a pulsed ionized sputtering process. This process is based on high power impulse magnetron sputtering, and high C ionization is achieved using Ne as the sputtering gas. The intrinsic compressive stress and its evolution with respect to ion energy and ion flux are explained in terms of the compressive stress based subplantation model for DLC growth by Davis. The highest mass density was similar to 2.7 g/cm(3), and the compressive stresses did not exceed similar to 2.5 GPa. The resulting film stresses are substantially lower than those achieved for the films exhibiting similar mass densities grown by filtered cathodic vacuum arc and pulsed laser deposition methods. This unique combination of high mass density and low compressive stress is attributed to the ion induced stress relaxation during the pulse-off time which corresponds to the post thermal spike relaxation timescales. We therefore propose that the temporal ion flux variations determine the magnitude of the compressive stress observed in our films. Published by AIP Publishing.

  • 30.
    Aijaz, Asim
    et al.
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden.;Uppsala Univ, Dept Engn Sci, Angstrom Lab, POB 534, SE-75121 Uppsala, Sweden..
    Louring, Sascha
    Aarhus Univ, Interdisciplinary Nanosci Ctr iNANO, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.;Danish Technol Inst, Tribol Ctr, Teknol Pk,Kongsvang Alle 29, DK-8000 Aarhus C, Denmark..
    Lundin, Daniel
    Univ Paris Saclay, Univ Paris Sud, LPGP, CNRS,UMR 8578, F-91405 Orsay, France..
    Kubart, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jensen, Jens
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Sarakinos, Kostas
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Helmersson, Ulf
    Linkoping Univ, Dept Phys Chem & Biol, IFM Mat Phys, SE-58183 Linkoping, Sweden..
    Synthesis of hydrogenated diamondlike carbon thin films using neon-acetylene based high power impulse magnetron sputtering discharges2016Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 34, nr 6, artikel-id 061504Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrogenated diamondlike carbon (DLC:H) thin films exhibit many interesting properties that can be tailored by controlling the composition and energy of the vapor fluxes used for their synthesis. This control can be facilitated by high electron density and/or high electron temperature plasmas that allow one to effectively tune the gas and surface chemistry during film growth, as well as the degree of ionization of the film forming species. The authors have recently demonstrated by adding Ne in an Ar-C high power impulse magnetron sputtering (HiPIMS) discharge that electron temperatures can be effectively increased to substantially ionize C species [Aijaz et al., Diamond Relat. Mater. 23, 1 (2012)]. The authors also developed an Ar-C2H2 HiPIMS process in which the high electron densities provided by the HiPIMS operation mode enhance gas phase dissociation reactions enabling control of the plasma and growth chemistry [Aijaz et al., Diamond Relat. Mater. 44, 117 (2014)]. Seeking to further enhance electron temperature and thereby promote electron impact induced interactions, control plasma chemical reaction pathways, and tune the resulting film properties, in this work, the authors synthesize DLC: H thin films by admixing Ne in a HiPIMS based Ar/C2H2 discharge. The authors investigate the plasma properties and discharge characteristics by measuring electron energy distributions as well as by studying discharge current characteristics showing an electron temperature enhancement in C2H2 based discharges and the role of ionic contribution to the film growth. These discharge conditions allow for the growth of thick (>1 mu m) DLC: H thin films exhibiting low compressive stresses (similar to 0.5 GPa), high hardness (similar to 25 GPa), low H content (similar to 11%), and density in the order of 2.2 g/cm(3). The authors also show that film densification and change of mechanical properties are related to H removal by ion bombardment rather than subplantation.

  • 31.
    Alberto, H. V.
    et al.
    Univ Coimbra, CFisUC, Dept Phys, R Larga, P-3004516 Coimbra, Portugal..
    Vilao, R. C.
    Univ Coimbra, CFisUC, Dept Phys, R Larga, P-3004516 Coimbra, Portugal..
    Vieira, R. B. L.
    Univ Coimbra, CFisUC, Dept Phys, R Larga, P-3004516 Coimbra, Portugal..
    Gil, J. M.
    Univ Coimbra, CFisUC, Dept Phys, R Larga, P-3004516 Coimbra, Portugal..
    Weidinger, A.
    Helmholtz Zentrum Berlin Mat & Energie, D-14109 Berlin, Germany..
    Sousa, M. G.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal..
    Teixeira, J. P.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal..
    da Cunha, A. F.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal..
    Leitao, J. P.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal..
    Salome, P. M. P.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal.;Int Iberian Nanotechnol Lab, P-4715330 Braga, Portugal..
    Fernandes, P. A.
    Univ Aveiro, I3N, Aveiro, Portugal.;Univ Aveiro, Dept Phys, Aveiro, Portugal.;Int Iberian Nanotechnol Lab, P-4715330 Braga, Portugal.;Inst Super Engn Porto, CIET, P-4200072 Oporto, Portugal.;Inst Super Engn Porto, Dept Phys, P-4200072 Oporto, Portugal..
    Törndahl, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Prokscha, T.
    Paul Scherrer Inst, Lab Muon Spin Spect, CH-5232 Villigen, Switzerland..
    Suter, A.
    Paul Scherrer Inst, Lab Muon Spin Spect, CH-5232 Villigen, Switzerland..
    Salman, Z.
    Paul Scherrer Inst, Lab Muon Spin Spect, CH-5232 Villigen, Switzerland..
    Slow-muon study of quaternary solar-cell materials: Single layers and p-n junctions2018Ingår i: PHYSICAL REVIEW MATERIALS, ISSN 2475-9953, Vol. 2, nr 2, artikel-id 025402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films and p-n junctions for solar cells based on the absorber materials Cu(In, Ga) Se-2 and Cu2ZnSnS4 were investigated as a function of depth using implanted low energy muons. The most significant result is a clear decrease of the formation probability of the Mu(+) state at the heterojunction interface as well as at the surface of the Cu(In, Ga)Se-2 film. This reduction is attributed to a reduced bonding reaction of the muon in the absorber defect layer at its surface. In addition, the activation energies for the conversion from a muon in an atomiclike configuration to a anion-bound position are determined from temperature-dependence measurements. It is concluded that the muon probe provides a measurement of the effective surface defect layer width, both at the heterojunctions and at the films. The CIGS surface defect layer is crucial for solar-cell electrical performance and additional information can be used for further optimizations of the surface.

  • 32. Ali, MP
    et al.
    Tove, PA
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Ibrahim, M
    Barrier height of evaporated manganese contacts to silicon1979Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 50, nr 11, s. 7250-Artikel i tidskrift (Refereegranskat)
  • 33. Ali, MP
    et al.
    Tove, PA
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Norde, Herman
    Junctions between amorphous and crystalline silicon1981Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, s. 339-400Artikel i tidskrift (Refereegranskat)
  • 34. Ali, MP
    et al.
    Tove, PA
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Stolt, Lars
    Barrier height of Fe contacts to Si1981Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 24, s. 408-409Artikel i tidskrift (Refereegranskat)
  • 35. Alnaimi, A
    et al.
    Berg, Sören
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Adhesion properties of carbon films1980Konferensbidrag (Refereegranskat)
  • 36. Andersson, G
    et al.
    Tove, PA
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jung, B
    Svensson, IB
    The isometric transitions in T1 197 and T1 1951957Ingår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 3, s. 493-Artikel i tidskrift (Refereegranskat)
  • 37.
    Andersson, Hugo
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Mattsson, Viktor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Senek, Aleksandar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Implementation of PID control using Arduino microcontrollers for glucose measurements and micro incubator applications2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The task is to build a low-cost thermostat and design necessary elements to perform a study on water mixed glucose-impedance at different temperatures and cell growth in a temperature-controlled incubator housing a magnetic field of up to 3 mT. The incubator was designed in solidworks and made to fit petri dishes of two relevant sizes and necessary wiring. The coils designed to extend across the large of the incubator with six turns and a 4A current to yield a sixth of the required magnetic field, as field strength increases linearly with current and turns increasing either of these is advised, and a large enough homogenous field was observed to create a suitable environment for the study. A thermistor, temperature sensitive resistance, was used to get reading and a modified wheatstone bridge was used with a multiplying op-amp to stabilize and improve accuracy of readings. Using an arduino microprocessor utilizing a PID library to calculate the power needed from thermistor readings of ambient temperature and an H-bridge controller by PWM from the Arduino a thermostat capable of driving a peltier-cell was produced capable of raising, lowering and maintaining predefined temperatures.