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Olsson, Jörgen
Alternative names
Publications (10 of 189) Show all publications
Hoang Duc, L., Jobs, M., Lofnes, T., Ruber, R., Olsson, J. & Dancila, D. (2019). Feedback compensated 10 kW solid-state pulsed power amplifier at 352 MHz for particle accelerators. Review of Scientific Instruments, 90(10), Article ID 104707.
Open this publication in new window or tab >>Feedback compensated 10 kW solid-state pulsed power amplifier at 352 MHz for particle accelerators
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2019 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 90, no 10, article id 104707Article in journal (Refereed) Published
Abstract [en]

This paper presents the first results of an in-house developed low-level radio frequency (LLRF) system and a 10 kW solid state power amplifier (SSPA). The design approach for the SSPA is based on eight resonant single-ended kilowatt modules combined using a planar Gysel combiner. Each of the single-ended modules is based on a two-stepped impedance resonant matching, allowing for harmonic suppression, simple design for massive production, and high-performance design. A design methodology to tune SSPA modules for optimum combining efficiency is presented thoroughly in the time domain. We characterize the power droop due to capacitor banks in the time domain. In open loop of compensation, it is about 1 kW within the pulse of peak value 10 kW and a duration of 3.5 ms. This may lead to the beam instability of the accelerator as particles are not provided with the same energy during the pulse. By incorporating our LLRF system, it is demonstrated that the objective of amplitude and phase stability is satisfied, as required in the European Spallation Source proton accelerator. The presented design also offers the advantages of compact form factor, low complexity, and better performance. In closed loop compensation, the variation of amplitude (pulse droop) is measured on the order of 20 W, which is equivalent to 0.2% at 10 kW peak output power.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-402616 (URN)10.1063/1.5110981 (DOI)000504078300062 ()
Available from: 2020-01-17 Created: 2020-01-17 Last updated: 2020-05-15Bibliographically approved
Hoang Duc, L., Bhattacharyya, A., Olsson, J. & Dancila, D. (2018). Implementation of a Highly Efficient Solid State RF Power Source for Superconducting Cavities. In: : . Paper presented at GigaHertz Symposium, Lund, May 24-25, 2018.
Open this publication in new window or tab >>Implementation of a Highly Efficient Solid State RF Power Source for Superconducting Cavities
2018 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-369239 (URN)
Conference
GigaHertz Symposium, Lund, May 24-25, 2018
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-14Bibliographically approved
Ahlberg, P., Hinnemo, M., Zhang, S.-L. & Olsson, J. (2018). Interface Dependent Effective Mobility in Graphene Field Effect Transistors. Journal of Electronic Materials, 47(3), 1757-1761
Open this publication in new window or tab >>Interface Dependent Effective Mobility in Graphene Field Effect Transistors
2018 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, no 3, p. 1757-1761Article in journal (Refereed) 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.

National Category
Engineering and Technology Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-284924 (URN)10.1007/s11664-017-6023-6 (DOI)000424341700002 ()
Funder
Knut and Alice Wallenberg Foundation, 2011.0082Swedish Research Council, 2014-5591
Available from: 2016-04-19 Created: 2016-04-19 Last updated: 2018-04-11Bibliographically approved
Hoang Duc, L., Bhattacharyya, A., Olsson, J. & Dancila, D. (2018). Optimal Power Consumption during the Charging of Superconducting Cavities using Drain Voltage Modulation of Solid State Power Amplifiers. In: : . Paper presented at GigaHertz Symposium, Lund, May 24-25, 2018.
Open this publication in new window or tab >>Optimal Power Consumption during the Charging of Superconducting Cavities using Drain Voltage Modulation of Solid State Power Amplifiers
2018 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-369219 (URN)
Conference
GigaHertz Symposium, Lund, May 24-25, 2018
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-14Bibliographically approved
Hinnemo, M., Makaraviciute, A., Ahlberg, P., Olsson, J., Zhang, Z., Zhang, S.-L. & Zhang, Z.-B. (2018). Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors. IEEE Sensors Journal, 18(16), 6497-6503
Open this publication in new window or tab >>Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors
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2018 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 18, no 16, p. 6497-6503Article in journal (Refereed) Published
Abstract [en]

Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-317088 (URN)10.1109/JSEN.2018.2849006 (DOI)000439966100003 ()
Funder
Knut and Alice Wallenberg Foundation, 2011.0113 2011.0082Swedish Foundation for Strategic Research , SE13-0061Swedish Research Council, 2014-5591 2014-5588
Available from: 2017-03-10 Created: 2017-03-10 Last updated: 2018-11-12Bibliographically approved
Hoang Duc, L., Bhattacharyya, A., Goryashko, V., Ruber, R., Olsson, J. & Dancila, D. (2018). Time Domain Characterization of High Power Solid State Amplifiers for the Next Generation Linear Accelerators. Microwave and optical technology letters (Print), 60(1), 163-171
Open this publication in new window or tab >>Time Domain Characterization of High Power Solid State Amplifiers for the Next Generation Linear Accelerators
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2018 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 60, no 1, p. 163-171Article in journal (Refereed) Published
Abstract [en]

This paper presents the time domain characterization of high power pulsed solid state amplifiers to be used forlinear accelerator applications. The study comprises nonlinear circuit envelope simulations and time domainenvelope measurements. Measurements and simulations are performed under the pulsed conditions (3.5 mspulse width, 5% duty cycle) specific to the European Spallation Source (ESS) high intensity proton accelerator.We measure the characteristics of pulsed LDMOS based power amplifiers such as: pulse droop along the pulse,efficiency, average envelope pulse amplitude and phase, pulse drain current waveform, pulse drain voltagewaveform, etc. A comparison between the measured results and the simulated results is also presented. Inaddition to the pulse profile characterization, the pulse to pulse (P2P) stability of the presented solid state poweramplifier (SSPA) is investigated as variations of amplitude and phase. The P2P stability simulations areintroduced as a combination of the Monte-Carlo simulations and the nonlinear circuit envelope simulations. Thesimulated results are used for fitting the P2P measurements to give an early insight of causes of instabilities ofthe nonlinear LDMOS models.

Keywords
accelerator, solid state amplifiers, LDMOS, nonlinear circuit envelope, time domain envelope measurements, pulse profile
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-334910 (URN)10.1002/mop.30926 (DOI)000416937700028 ()
Projects
ESS
Available from: 2017-11-29 Created: 2017-11-29 Last updated: 2019-11-21Bibliographically approved
Szaniawski, P., Olsson, J., Frisk, C., Fjällström, V., Ledinek, D., Larsson, F., . . . Edoff, M. (2017). A Systematic Study of Light-On-Bias Behavior in Cu(In,Ga)Se2 Solar Cells With Varying Absorber Compositions. IEEE Journal of Photovoltaics, 7(3), 882-891
Open this publication in new window or tab >>A Systematic Study of Light-On-Bias Behavior in Cu(In,Ga)Se2 Solar Cells With Varying Absorber Compositions
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2017 (English)In: IEEE Journal of Photovoltaics, ISSN 2156-3381, E-ISSN 2156-3403, Vol. 7, no 3, p. 882-891Article in journal (Refereed) Published
Abstract [en]

Light-on-bias effects were investigated in multiple Cu(In, Ga)Se2 solar cells with varying absorber layer compositions. A strong link between deformations caused by red-on-bias treatments in current-voltage (IV ) and capacitance-voltage (CV) characteristics was demonstrated. Similarly to red-on-bias, blue-on-bias leads to a local increase in static negative charge, but in samples with CdS buffers this increase is shifted away from the interface and has no impact on device performance. IV characteristics of samples with Cd-free buffers are not affected by any light-on-bias treatments, suggesting that CdS plays a vital role in the decreased performance after red-on-bias. A statistical approach was used to search for compositional trends in red-on-bias behavior. Deformation factors were defined for IV and CV characteristics before and after the treatment. While there is a strong relationship between the deformations observed in both types of measurements, the degree to which red-on-bias affects IV and CV curves can vary dramatically. These variations cannot be attributed to changes in composition, since no clear compositional trends were found. Rather, other factors related to sample manufacturing and to the buffer layer seem to have major impact on red-on-bias behavior.

Keywords
Capacitance;Charge measurement;Current measurement;Light emitting diodes;Lighting;Photovoltaic cells;Temperature measurement;Capacitance-voltage characteristics;current-voltage characteristics;degradation;deposition and characterization of thin film PV absorbers;photovoltaic cells;photovoltaic effects;thin film PV device properties and modeling
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-319426 (URN)10.1109/JPHOTOV.2017.2655148 (DOI)000399992000023 ()
Available from: 2017-04-04 Created: 2017-04-04 Last updated: 2018-07-13Bibliographically approved
Szaniawski, P., Zabierowski, P., Olsson, J., Zimmermann, U. & Edoff, M. (2017). Advancing the understanding of reverse breakdown in Cu(In,Ga)Se2 solar cells. IEEE Journal of Photovoltaics, 7(4), 1136-1142
Open this publication in new window or tab >>Advancing the understanding of reverse breakdown in Cu(In,Ga)Se2 solar cells
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2017 (English)In: IEEE Journal of Photovoltaics, ISSN 2156-3381, E-ISSN 2156-3403, Vol. 7, no 4, p. 1136-1142Article in journal (Refereed) Published
Abstract [en]

Reverse breakdown is investigated in multiple Cu(In,Ga)Se-2 solar cells with varying buffer layer thicknesses. A method to extract transition voltage, which marks the change of conduction mechanism that leads to electrical breakdown, is described as an alternative to the often less-meaningful breakdown voltage. Transition voltages for samples with CdS and ZnxSn1-xOy buffers are extracted from breakdown measurements performed in darkness and under illumination. The electric field is calculated for ZTO-based samples measured in darkness, and its implications for the energy band structure are examined. Fowler-Nordheim tunneling and Poole-Frenkel conduction are considered as candidates for the main breakdown mechanism in darkness. A model combining the two conduction mechanisms is proposed, and fits for experimental data are presented and discussed. Involvement of defects is debated, and defect-andbreakdown- related phenomena are showcased.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-319442 (URN)10.1109/JPHOTOV.2017.2699860 (DOI)000404258900027 ()
Available from: 2017-04-04 Created: 2017-04-04 Last updated: 2017-09-12Bibliographically approved
Frisk, C., Ren, Y., Olsson, J., Törndahl, T., Annoni, F. & Platzer Björkman, C. (2017). On the extraction of doping concentration from capacitance-voltage: A Cu2ZnSnS4 and ZnS sandwich structure. IEEE Journal of Photovoltaics, 7(5), 1421-1425
Open this publication in new window or tab >>On the extraction of doping concentration from capacitance-voltage: A Cu2ZnSnS4 and ZnS sandwich structure
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2017 (English)In: IEEE Journal of Photovoltaics, ISSN 2156-3381, E-ISSN 2156-3403, Vol. 7, no 5, p. 1421-1425Article in journal (Refereed) Published
Abstract [en]

The capacitance-voltage (C-V) method is frequently used to evaluate the net doping of thin-film solar cells, an important parameter for the function of solar cells. However, complex materials such as kesterites are challenging to characterize. To minimize ambiguity when determining the apparent doping concentration (N-A) of Cu2ZnSnS4 (CZTS), we fabricated and investigated different structures: CZTS/ZnS metal-insulator-semiconductor (MIS) device, stand-alone CZTS and ZnS metal-sandwich structures, and CZTS solar cells. Characterization was carried out by means of admittance spectroscopy (AS) and C-V measurements. ZnS exhibits excellent intrinsic properties, and with the high-quality MIS sample we managed to successfully isolate the capacitive response of the CZTS itself. N-A, as extracted from the MIS structure, is found to be more reliable and four times higher compared with the solar cell, impacting any estimated collection efficiency substantially. Data herein presented also show that CZTS has a substantial low-frequency dispersive capacitance and the extraction of N-A depends on the chosen measurement frequency, symptoms of presence of deep defects. Furthermore, the CZTS/ZnS MIS structure is strongly resilient to leakage currents at both forward and reverse voltage bias where contribution from deep defects is minimized and maximized, respectively.

Keywords
Admittance measurement, capacitance-voltage characteristics, kesterite, modeling, semiconductor device doping
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-320307 (URN)10.1109/JPHOTOV.2017.2711427 (DOI)000408160700034 ()
Funder
Swedish Research CouncilSwedish Energy AgencyKnut and Alice Wallenberg Foundation
Available from: 2017-04-18 Created: 2017-04-18 Last updated: 2017-10-03
Olsson, J., Vestling, L. & Eklund, K.-H. (2016). A New Latch-Free LIGBT on SOI with Very High Current Density and Low Drive Voltage. Solid-State Electronics, 115, 179-184
Open this publication in new window or tab >>A New Latch-Free LIGBT on SOI with Very High Current Density and Low Drive Voltage
2016 (English)In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 115, p. 179-184Article in journal (Refereed) Published
Abstract [en]

A new latch-free LIGBT on SOI is presented. The new device combines advantages from both LDMOS as well as LIGBT technologies; high breakdown voltage, high drive current density, low control voltages, at the same time eliminating latch-up problems. The new LIGBT has the unique property of independent scaling of the input control device, i.e. LDMOS, and the output part of the device, i.e. the p-n-p part. This allows for additional freedom in designing and optimizing the device properties. Breakdown voltage of over 200 V, on-state current density over 3 A/mm, specific on-resistance below 190 mWmm2, and latch-free operation is demonstrated.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-259478 (URN)10.1016/j.sse.2015.08.011 (DOI)000365614500017 ()
Funder
VINNOVA
Available from: 2015-08-05 Created: 2015-08-05 Last updated: 2017-12-04Bibliographically approved
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