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Larsson, Karin
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Publications (10 of 123) Show all publications
Choudhury, S., Petit, T., Ren, J., Kiendl, B., Gao, F., Nebel, C., . . . Aziz, E. (2017). Altering Mid-Gap Acceptor Levels by Morphology Tuning of Boron Doped Diamonds. In: : . Paper presented at 2017 MRS Fall Meeting & Exhibit, November 26-December 1, 2017 Boston, Massachusetts, USA.
Open this publication in new window or tab >>Altering Mid-Gap Acceptor Levels by Morphology Tuning of Boron Doped Diamonds
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2017 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Hydrogen terminated diamond is a very promising material for high energy photocatalytic reactions1 owing to its large band gap(5.5 eV) and a unique capability of generating solvated electrons due to its negative electron affinity.2 However, a major limitation to the photoexcitation process to create solvated electrons is the need for deep UV illumination. Introducing unoccupied electronic states within the band gap of diamonds by doping with boron could provide a potential pathway for photoexcitation using visible light.Previous reports on HRTEM and EELS study of B doped polycrystalline and nanocrystalline diamonds provide insights into the local B environment.4,5,6,7 However, since these are primarily electron in-electron out techniques, they do not provide sufficient information about the existence of acceptor levels in the band gap of diamonds that are associated with boron doping. X-ray spectroscopy techniques have been shown to be sensitive to the acceptor levels arising due to boron doping.3 However, their physical origin still remains unclear.Here we use soft X-ray absorption spectroscopy (XAS) to probe the unoccupied electronic states at the carbon K edge in different boron-doped diamond materials, ranging from single crystal and polycrystalline film to diamond foam and nanodiamonds with different sizes. XAS of carbon K edges for the different B doped diamonds were characterized using partial fluorescence yield at the BESSY II synchrotron facility. Combining these results with density functional theory calculations, here we elucidate the contribution of the environment of boron to these mid gap acceptor states that vary with the morphology of diamonds. These results could have important implications on the selection of a suitable diamond based visible-light photocatalysts.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-338640 (URN)
Conference
2017 MRS Fall Meeting & Exhibit, November 26-December 1, 2017 Boston, Massachusetts, USA
Note

Symposium session EM06 : Diamond Electronics, Sensors and Biotechnology—Fundamentals to Applications

EM06.14.02

Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-02-16Bibliographically approved
Wu, X., Bruschi, M., Waag, T., Schweeberg, S., Tian, Y., Meinhardt, T., . . . Krueger, A. (2017). Functionalization of bone implants with nanodiamond particles and angiopoietin-1 to improve vascularization and bone regeneration. Journal of materials chemistry. B, 5(32), 6629-6636
Open this publication in new window or tab >>Functionalization of bone implants with nanodiamond particles and angiopoietin-1 to improve vascularization and bone regeneration
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2017 (English)In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 5, no 32, p. 6629-6636Article in journal (Refereed) Published
Abstract [en]

One of the major challenges in bone tissue engineering is adequate vascularization within bone substituents for nutrients and oxygen supply. In this study, the production and results of a new, highly functional bone construct consisting of a commercial three-dimensional beta-tricalcium phosphate scaffold (beta-TCP, ChronOS (R)) and hydrophilic, functionalized nanodiamond (ND) particles are reported. A 30-fold increase in the active surface area of the ChronOS + ND scaffold was achieved after modification with ND. In addition, immobilization of angiopoietin-1 (Ang-1) via physisorption within the beta-TCP + ND scaffold retained the bioactivity of the growth factor. Homogeneous distribution of the ND and Ang-1 within the core of the three-dimensional scaffold was confirmed using ND covalently labelled with Oregon Green. The biological responses of the beta-TCP + ND scaffold with and without Ang-1 were studied in a sheep calvaria critical size defect model showing that the beta-TCP + ND scaffold improved the blood vessel ingrowth and the beta-TCP + ND + ND + Ang-1 scaffold further promoted vascularization and new bone formation. The results demonstrate that the modification of scaffolds with tailored diamond nanoparticles is a valuable method for improving the characteristics of bone implants and enables new approaches in bone tissue engineering.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-333753 (URN)10.1039/c7tb00723j (DOI)000407684800019 ()
Available from: 2017-11-16 Created: 2017-11-16 Last updated: 2017-11-16Bibliographically approved
Choudhury, S., Petit, T., Ren, J., Kiendl, B., Gao, F., Nebel, C., . . . Aziz, E. (2017). Influence of size on boron acceptor levels in boron doped diamonds: An X-ray absorption spectroscopy study. In: : . Paper presented at Hasselt Diamond Workshop 2017 - SBDD XXII.
Open this publication in new window or tab >>Influence of size on boron acceptor levels in boron doped diamonds: An X-ray absorption spectroscopy study
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2017 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-338638 (URN)
Conference
Hasselt Diamond Workshop 2017 - SBDD XXII
Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-01-11
Larsson, K. (2017). The Effect of Dopants on Diamond Surface Properties and Growth. Springer
Open this publication in new window or tab >>The Effect of Dopants on Diamond Surface Properties and Growth
2017 (English)Book (Other academic)
Place, publisher, year, edition, pages
Springer, 2017
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-338643 (URN)
Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-01-31
Kiendl, B., Levitre, G., Hadzifejzovic, E., Lounasvuori, M., Venerosy, A., Choudhury, S., . . . Krueger, A. (2017). Transition-Metal Functionalized Nanodiamond for Photocatalytic Applications. In: : . Paper presented at 2017 MRS Fall Meeting & Exhibit, November 26-December 1, 2017, Boston, USA.
Open this publication in new window or tab >>Transition-Metal Functionalized Nanodiamond for Photocatalytic Applications
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2017 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-338639 (URN)
Conference
2017 MRS Fall Meeting & Exhibit, November 26-December 1, 2017, Boston, USA
Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-02-23Bibliographically approved
Zou, Y. & Larsson, K. (2016). Effect of Boron Doping on the CVD Growth Rate of Diamond. The Journal of Physical Chemistry C, 120(19), 10658-10666
Open this publication in new window or tab >>Effect of Boron Doping on the CVD Growth Rate of Diamond
2016 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 19, p. 10658-10666Article in journal (Refereed) Published
Abstract [en]

The purpose with the present study has been to theoretically investigate the effect of boron doping on the diamond growth rate. The most frequently observed diamond surface planes (100), (111) and (110) were thereby carefully investigated using density functional theory calculations under periodic boundary conditions. It was shown that both the thermodynamic and kinetic aspects of the diamond growth process will be severely affected by the B dopant (as compared with the non-doped situations). More specifically, the results showed that B (positioned within the 2nd atomic C layer) will cause an enhancement in the growth rate. On the other hand, the effect of B positioned in the other atomic C layers showed a decreased growth rate. These observations did not only correlate with experimental results but did also explain the anomalous variations in the diamond growth rate (i.e., either increase or decrease) with B doping.

Keywords
Diamond, Growth rate, CVD, Ab initio theory, B doping
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-271512 (URN)10.1021/acs.jpcc.6b02227 (DOI)000376417500059 ()
External cooperation:
Funder
Swedish Research Council
Available from: 2016-01-08 Created: 2016-01-08 Last updated: 2017-12-01Bibliographically approved
Shuainan, Z. & Karin, L. (2016). First principle study of the attachment of graphene onto non-doped and doped diamond (111). Diamond and related materials, 66, 52-60
Open this publication in new window or tab >>First principle study of the attachment of graphene onto non-doped and doped diamond (111)
2016 (English)In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 66, p. 52-60Article in journal (Refereed) Published
Abstract [en]

Density function theory (DFT) calculations have in the present study been used to study the adhesion of a graphene monolayer onto a non-, B-, or N-doped diamond (111) surface. Semiempirical dispersion corrections were used to take the Van-der-Waals corrections into consideration. In case of non-doped diamond as a substrate, DFT calculations (based on the local density approximation (LDA)) have shown a strong binding between graphene and the diamond (111) surface at a shorter distance (2.47 Å). The binding energy was − 14.5 kJ/mol per Cgraphene atom. In comparison, the generalized gradient spin density approximation (GG(S)A) was found to predict a weaker (− 9.6 kJ/mol) interfacial bond at a distance of 3.10 Å. For the situation with B-, or N-, doped diamond, the optimized shorter diamond-graphene distance was found to be 3.01 and 3.24 Å, respectively. The corresponding adhesion energies per Cgraphene atom was − 9.9 kJ/mol (B-doping) and − 9.6 kJ/mol (N-doping), which are quite similar to the non-doped situation (− 9.6 kJ/mol). For all situations in the present study, the graphene layer was found to remain its aromatic character. However, a minor charge transfer was observed to take place from the graphene adlayer towards the non-doped and doped diamond (111) substrates.

Keywords
Density functional theory; Epitaxial graphene; Diamond substrate; Charge transfer
National Category
Inorganic Chemistry
Research subject
Chemistry with specialization in Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-283287 (URN)10.1016/j.diamond.2016.03.017 (DOI)000379633000007 ()
Funder
Swedish Research Council, VR 2012-4107
Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-11-30Bibliographically approved
Song, Y. & Larsson, K. (2015). A Theoretical Study of the Effect of Dopants on Diamond (100) Surface Stabilization for Different Termination Scenarios. The Journal of Physical Chemistry C, 119(5), 2545-2556
Open this publication in new window or tab >>A Theoretical Study of the Effect of Dopants on Diamond (100) Surface Stabilization for Different Termination Scenarios
2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 5, p. 2545-2556Article in journal (Refereed) Published
Abstract [en]

The effect of dopants (N or B) on differently terminated diamond (100)-2 × 1 surfaces has in the present study been studied theoretically by using DFT (density functional theory) under periodic boundary conditions. The terminating species, X, include H, OH, Oontop, and Obridge. As a result of geometry optimization, the C–N and C–B bond lengths were calculated to be longer than for the situation with saturated binding conditions (i.e., the situation where N (or B) are binding to three other atoms, instead of four). Moreover, the X–Csurface-dopant angles were observed to decrease for the N-doped and increase for the B-doped senarios. In addition, the atomic charges and bond populations for the region surrounding the dopants were also carefully analyzed in order to compare the surface stabilization situations for non-, N- and B-doped diamond surfaces. For the H-terminated diamond surfaces, the C–H bonds became weakened when substituationally doped with either N or B. For the O-terminated diamond surfaces (i.e., both Oontop, and Obridge), the results showed opposite trends by strengthening (or weakening) the C–O bonds for the N- (or B-) doped system, respectivly. The adsorption energies for the various terminating species were observed to decrease when going from a nondoped to an N-doped situation and finally over to a B-doped situation. This is a result that strongly correlates with the calculated Csurface–X (X = H, OH, Oontop, Obridge) bond lengths. In addition, the effect of surface termination on the diamond surface stabilization energy, was observed to be in the following order: Obridge > Otop > H > OH. This result was valid for both non-, N- and B-doped diamond surfaces. The calculated spin density calculations indicated a local distribution of the unpaired electron in the N- and B-doped systems, respectively. This is a result that showed a strong correlation to the bond lengths surrounding the dopants and to the calculated adsorption energies for the terminating species, X. Moreover, the surface electronic structures (i.e., surface states) for the N- and B-doped systems were calculated and visualized by performing pDOS calculations. The results showed a shift of the Fermi levels for the N- and B-doped situations. As expected, the Fermi level was shifted toward the conduction band for the N-doped surfaces and toward the valence band for the B-doped systems. In addition, the pDOS spectra for the Oontop-termination showed extra states around the Fermi level, which were the result induced by the radical nature of this type of termination species.

Place, publisher, year, edition, pages
Washington, DC: , 2015
Keywords
Diamond, surface terminations, dopants
National Category
Materials Chemistry
Research subject
Chemistry with specialization in Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-242826 (URN)10.1021/jp511077v (DOI)000349136400035 ()
Projects
MATCON
Funder
EU, FP7, Seventh Framework Programme, MATCON-238201
Available from: 2015-02-02 Created: 2015-02-02 Last updated: 2017-12-05Bibliographically approved
Tian, Y. & Larsson, K. (2015). Protein-Functionalized Diamond Surfaces in a Water Solvent: A Theoretical Approach. The Journal of Physical Chemistry C, 119(16), 8608-8618
Open this publication in new window or tab >>Protein-Functionalized Diamond Surfaces in a Water Solvent: A Theoretical Approach
2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 16, p. 8608-8618Article in journal (Refereed) Published
Abstract [en]

In order to improve the performance of a diamond-based implant material, surface functionalization with different proteins is a promising approach. The main goal of the present study has been to theoretically investigate the diamond functionalization by physisorption of different proteins onto different surface planes. The protein candidates selected are growth factors which can promote cell adhesion and growth and subsequent vascularization surrounding the implanted materials. They include Bone Morphogenetic Protein 2 (BMP2), Vascular Endothelial Growth Factor (VEGF), Fibronectin (FN), and Angiopoietin (AGP). Moreover, it is well-known that diamond surface properties are strongly dependent on diamond surface planes and surface terminations. Therefore, the following two different diamond surface planes [diamond (100)-2 x 1 and diamond (111)] and four different kinds of terminations species (H, OH, COOH, and NH2) were used in the present study. The results from force-field calculations show that the surface wettability is crucial for the protein adhesion onto the diamond surfaces, and the different proteins possess distinct preferences for diamond surface planes and terminations. For the identification of protein functionality, the atomic structures, in addition to corresponding electrostatic maps, were also visualized in the comparison of protein structures before and after adhesion to the diamond surfaces. It could be concluded that the protein structures and binding pocket electrostatic distributions are maintained as a result of the functionalization process, regardless of adhesion energy strength. These results provide a solid base for experimental protein functionalization of the diamond surfaces.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-255291 (URN)10.1021/jp511015m (DOI)000353603500023 ()
Available from: 2015-06-22 Created: 2015-06-15 Last updated: 2017-12-04Bibliographically approved
Tsigkourakos, M., Hantschel, T., Xu, Z., Douhard, B., Meersschaut, J., Zou, Y., . . . Vandervorst, W. (2015). Suppression of boron incorporation at the early growth phases of boron-doped diamond thin films. Physica Status Solidi (a) applications and materials science, 212(11), 2595-2599
Open this publication in new window or tab >>Suppression of boron incorporation at the early growth phases of boron-doped diamond thin films
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2015 (English)In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 212, no 11, p. 2595-2599Article in journal (Refereed) Published
Abstract [en]

The presence of O during the chemical vapour deposition (CVD) of B-doped diamond results in the suppression of B incorporation into the diamond film. In this study, we demonstrate that the amount of residual O within the chamber is higher at the beginning of the diamond growth due to the O-contaminated chamber walls, and is decreased after a certain time period. This leads to a gradual increase of the B incorporation by more than one order of magnitude during the early growth phases of nanocrystalline diamond (NCD). We further show that this suppression of B incorporation at the early growth phases of B-doped diamond is influenced by the growth rate of the film. This is attributed to the constant time period whereby most of the residual O interacts with the B-precursors in the gas phase by forming stable B-O species, which are flushed out from the chamber exhaust. Furthermore, the constant B profile of an NCD film grown in a loadlock hot-filament CVD (HFCVD) system reveals that the amount of residual O is constant and minimal during the growth process. Therefore, our work proves that the use of a loadlock overcomes the B-suppression problem at the early growth phases of diamond, making it the optimal solution for the growth of highly conductive thin diamond films.

Keywords
boron, chemical vapour deposition, diamond, doping, oxygen, secondary ion mass spectroscopy
National Category
Condensed Matter Physics Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-274349 (URN)10.1002/pssa.201532185 (DOI)000366588100034 ()
Available from: 2016-01-21 Created: 2016-01-21 Last updated: 2017-11-30Bibliographically approved
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