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Stehr, J. E., Balagula, R., Jansson, M., Yukimune, M., Fujiwara, R., Ishikawa, F., . . . Buyanova, I. A. (2020). Effects of growth temperature and thermal annealing on optical quality of GaNAs nanowires emitting in the near-infrared spectral range. Nanotechnology, 31(6), Article ID 065702.
Open this publication in new window or tab >>Effects of growth temperature and thermal annealing on optical quality of GaNAs nanowires emitting in the near-infrared spectral range
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2020 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 31, no 6, article id 065702Article in journal (Refereed) Published
Abstract [en]

We report on optimization of growth conditions of GaAs/GaNAs/GaAs core/shell/shell nanowire (NW) structures emitting at ~1 μm, aiming to increase their light emitting efficiency. A slight change in growth temperature is found to critically affect optical quality of the active GaNAs shell and is shown to result from suppressed formation of non-radiative recombination (NRR) centers under the optimum growth temperature. By employing the optically detected magnetic resonance spectroscopy, we identify gallium vacancies and gallium interstitials as being among the dominant NRR defects. The radiative efficiency of the NWs can be further improved by post-growth annealing at 680 °C, which removes the gallium interstitials.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2020
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-161947 (URN)10.1088/1361-6528/ab51cd (DOI)000502786100001 ()31658456 (PubMedID)
Note

Funding agencies:  Swedish Energy AgencySwedish Energy Agency [P40119-1]; Swedish Research CouncilSwedish Research Council [2015-05532]; Swedish Foundation for International Cooperation in Research and Higher Education (STINT) [JA2014-5698]; Swedish Government Strategic Res

Available from: 2019-11-14 Created: 2019-11-14 Last updated: 2020-01-02Bibliographically approved
Zhang, B., Huang, Y., Stehr, J. E., Chen, P., Wang, X. J., Lu, W., . . . Buyanova, I. A. (2019). Band structure of wurtzite GaBiAs nanowires. Nano letters (Print), 19, 6454-6460
Open this publication in new window or tab >>Band structure of wurtzite GaBiAs nanowires
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2019 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, p. 6454-6460Article in journal (Refereed) Published
Abstract [en]

We report on the first successful growth of wurtzite (WZ) GaBiAs nanowires (NWs) and reveal the effects of Bi incorporation on the electronic band structure by using polarization-resolved optical spectroscopies performed on individual NWs. Experimental evidence of a decrease in the band-gap energy and an upward shift of the topmost three valence subbands upon the incorporation of Bi atoms is provided, whereas the symmetry and ordering of the valence band states remain unchanged, that is, Γ9, Γ7, and Γ7 within the current range of Bi compositions. The extraordinary valence band structure of WZ GaBiAs NWs is explained by anisotropic hybridization and anticrossing between p-like Bi states and the extended valence band states of host WZ GaAs. Moreover, the incorporation of Bi into GaAs is found to significantly reduce the temperature sensitivity of the band-gap energy in WZ GaBiAs NWs. Our work therefore demonstrates that utilizing dilute bismide alloys provides new avenues for band-gap engineering and thus photonic engineering with NWs.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-160735 (URN)10.1021/acs.nanolett.9b02679 (DOI)000486361900080 ()2-s2.0-85072133061 (Scopus ID)
Note

Funding agencies: Linkoping University; Swedish Research CouncilSwedish Research Council [2016-05091]; Swedish Energy AgencySwedish Energy Agency [P40119-1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [20

Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-11-06Bibliographically approved
Stehr, J. E., Chen, S., Chen, W., Cai, L., Shen, S. & Buyanova, I. A. (2019). Effects of N implantation on defect formation in ZnO nanowires. Paper presented at 7th International Symposium on Transparent Conductive Materials (TCM). Thin Solid Films, 687, Article ID UNSP 137449.
Open this publication in new window or tab >>Effects of N implantation on defect formation in ZnO nanowires
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2019 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 687, article id UNSP 137449Article in journal (Refereed) Published
Abstract [en]

One-dimensional ZnO nanowires are a promising material system for a wide range of optoelectronic and photonic applications. Utilization of ZnO, however, requires high-quality ZnO with reliable n-type and p-type conductivity, with the latter remaining elusive, so far. In this work we report on effects of N doping via ion implantation on defect formation in ZnO nanowires studied by optically detected paramagnetic resonance (ODMR) spectroscopy complemented by photoluminescence spectroscopy. After N implantation, zinc interstitial shallow donors, which are formed as a result of ion implantation, are observed in addition to effective mass type shallow donors. Additionally, ODMR signals related to oxygen vacancies can be observed. Implantation also causes formation of a new nitrogen related defect center, which acts as an acceptor. The present findings are of importance for understanding impacts of different defects and impurities on electronic properties of nanostructured ZnO and achieving p-type conductivity via nitrogen doping.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2019
Keywords
Zinc oxide; Optically detected magnetic resonance; Photoluminescence; Defects; Nitrogen
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-160580 (URN)10.1016/j.tsf.2019.137449 (DOI)000485255100006 ()
Conference
7th International Symposium on Transparent Conductive Materials (TCM)
Note

Funding Agencies|Swedish Energy AgencySwedish Energy Agency [43522-1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; AForsk Foundation [15-433]

Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2019-10-17Bibliographically approved
Stehr, J. E., Hofmann, D., Schörmann, J., Becker, M., Chen, W. & Buyanova, I. A. (2019). Electron paramagnetic resonance signatures of Co2+ and Cu2+ in β-Ga2O3 [Letter to the editor]. Applied Physics Letters, 115(24), Article ID 242101.
Open this publication in new window or tab >>Electron paramagnetic resonance signatures of Co2+ and Cu2+ in β-Ga2O3
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2019 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 115, no 24, article id 242101Article in journal, Letter (Refereed) Published
Abstract [en]

Gallium oxide (β-Ga2O3) is a wide-bandgap compound semiconductor with a bandgap of ∼4.9 eV that is currently considered promising for a wide range of applications ranging from transparent conducting electrodes to UV optoelectronic devices and power electronics. However, all of these applications require a reliable and precise control of electrical and optical properties of the material, which can be largely affected by impurities, such as transition metals commonly present during the growth. In this work, we employ electron paramagnetic resonance (EPR) spectroscopy to obtain EPR signatures of the 3d-transition metals Co2+ and Cu2+ in β-Ga2O3 bulk crystals and powders that were unknown so far. Furthermore, we show that both Co2+ and Cu2+ preferentially reside on the octahedral gallium lattice site.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-162638 (URN)10.1063/1.5127651 (DOI)000505734100009 ()
Note

Funding agencies:  Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]

Available from: 2019-12-12 Created: 2019-12-12 Last updated: 2020-01-22Bibliographically approved
Stehr, J. E., Chen, W., Pearton, S., Uecker, R., Hofmann, D. & Buyanova, I. A. (2019). Electron paramagnetic resonance signatures of defects and impurities in β-Ga2O3. In: : . Paper presented at 30th International Conference on Defects in Semiconductors, Seattle, Washington, USA, July 21-26, 2019.
Open this publication in new window or tab >>Electron paramagnetic resonance signatures of defects and impurities in β-Ga2O3
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2019 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-160096 (URN)
Conference
30th International Conference on Defects in Semiconductors, Seattle, Washington, USA, July 21-26, 2019
Available from: 2019-09-05 Created: 2019-09-05 Last updated: 2019-09-12Bibliographically approved
Stehr, J. E., Lundström, I. & Karlsson, J. O. (2019). Evidence that fodipir (DPDP) binds neurotoxic Pt2+ with a high affinity: An electron paramagnetic resonance study. Scientific Reports, 9, Article ID 15813.
Open this publication in new window or tab >>Evidence that fodipir (DPDP) binds neurotoxic Pt2+ with a high affinity: An electron paramagnetic resonance study
2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 15813Article in journal (Refereed) Published
Abstract [en]

Oxaliplatin typically causes acute neuropathic problems, which may, in a dose-dependent manner, develop into a chronic form of chemotherapy-induced peripheral neuropathy (CIPN), which is associated with retention of Pt2+ in the dorsal root ganglion. A clinical study by Coriat and co-workers suggests that co-treatment with mangafodipir [Manganese(II) DiPyridoxyl DiPhosphate; MnDPDP] cures ongoing CIPN. These authors anticipated that it is the manganese superoxide dismutase mimetic activity of MnDPDP that explains its curative activity. However, this is questionable from a pharmacokinetic perspective. Another, but until recently undisclosed possibility is that Pt2+ outcompetes Mn2+/Ca2+/Zn2+ for binding to DPDP or its dephosphorylated metabolite PLED (diPyridoxyL EthylDiamine) and transforms toxic Pt2+ into a non-toxic complex, which can be readily excreted from the body. We have used electron paramagnetic resonance guided competition experiments between MnDPDP (10logKML ≈ 15) and K2PtCl4, and between MnDPDP and ZnCl2 (10logKML ≈ 19), respectively, in order to obtain an estimate the 10logKML of PtDPDP. Optical absorption spectroscopy revealed a unique absorption line at 255 nm for PtDPDP. The experimental data suggest that PtDPDP has a higher formation constant than that of ZnDPDP, i.e., higher than 19. The present results suggest that DPDP/PLED has a high enough affinity for Pt2+ acting as an efficacious drug in chronic Pt2+-associated CIPN.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
National Category
Biophysics Pharmacology and Toxicology
Identifiers
urn:nbn:se:liu:diva-161652 (URN)10.1038/s41598-019-52248-9 (DOI)000493716000014 ()31676855 (PubMedID)2-s2.0-85074277794 (Scopus ID)
Funder
Medical Research Council of Southeast Sweden (FORSS), 85191
Note

Funding agencies: Medical Research Council of Southeast Sweden [FORSS-85191]; Karlsson-Tuner Invest AS, Norway

Available from: 2019-11-05 Created: 2019-11-05 Last updated: 2019-12-13Bibliographically approved
Stehr, J. E., Chen, S., Chen, W., Cai, L., Shen, S. & Buyanova, I. A. (2019). Identification of a N-related acceptor in ZnO nanowires. In: : . Paper presented at 30th International Conference on Defects in Semiconductors, Seattle, Washington, USA, July 21-26, 2019.
Open this publication in new window or tab >>Identification of a N-related acceptor in ZnO nanowires
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2019 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-160099 (URN)
Conference
30th International Conference on Defects in Semiconductors, Seattle, Washington, USA, July 21-26, 2019
Available from: 2019-09-05 Created: 2019-09-05 Last updated: 2019-09-13Bibliographically approved
Rudko, G., Vorona, I. P., Dzhagan, V. M., Raevskaya, A. E., Stroyuk, O. L., Fediv, V. I., . . . Buyanova, I. A. (2019). Optically detected magnetic resonance study of relaxation/emission processes in the nanoparticle-polymer composite. SPQEO, 22(3), 310-318
Open this publication in new window or tab >>Optically detected magnetic resonance study of relaxation/emission processes in the nanoparticle-polymer composite
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2019 (English)In: SPQEO, ISSN 1605-6582, Vol. 22, no 3, p. 310-318Article in journal (Refereed) Published
Abstract [en]

Two nanocomposites containing CdS nanoparticles in polymeric matrices were studied using the photoluminescence (PL) and optically detected magnetic resonance (ODMR) methods. Due to equal sizes of NPs in the composites (~5 nm) but different matrices – the oxygen-containing polymer PVA (polyvinyl alcohol) and oxygen-free polymer PEI (polyethyleneimine) – differences of nanocomposites properties are predominantly caused by different interfacial conditions. ODMR spectra have revealed five types of centers related to the PL emission – four centers involved in radiative recombination and one center related to non-radiative recombination processes. The oxygen-related interfacial center in CdS/PVA (LK1-center) and sulfur vacancy center in CdS/PEI (Vs-center) were identified.

Place, publisher, year, edition, pages
Kiev, Ukraine: Natsional'na Akademiya Nauk Ukrainy * Instytut Fizyky Napivprovidnykiv, 2019
Keywords
CdS nanoparticles, polymer, composites, photoluminescence, optically detected magnetic resonance
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-160736 (URN)10.15407/spqeo22.03.310 (DOI)000485820300006 ()
Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-12-03Bibliographically approved
Stehr, J. E., Buyanova, I. A. & Chen, W. (Eds.). (2018). Defects in Advanced Electronic Materials and Novel Low Dimensional Structures (1ed.). Woodhead Publishing Limited
Open this publication in new window or tab >>Defects in Advanced Electronic Materials and Novel Low Dimensional Structures
2018 (English)Collection (editor) (Other academic)
Abstract [en]

Defects in Advanced Electronic Materials and Novel Low Dimensional Structures provides a comprehensive review on the recent progress in solving defect issues and deliberate defect engineering in novel material systems. It begins with an overview of point defects in ZnO and group-III nitrides, including irradiation-induced defects, and then look at defects in one and two-dimensional materials, including carbon nanotubes and graphene. Next, it examines the ways that defects can expand the potential applications of semiconductors, such as energy upconversion and quantum processing. The book concludes with a look at the latest advances in theory.

While defect physics is extensively reviewed for conventional bulk semiconductors, the same is far from being true for novel material systems, such as low-dimensional 1D and 0D nanostructures and 2D monolayers. This book fills that necessary gap.

Place, publisher, year, edition, pages
Woodhead Publishing Limited, 2018. p. 306 Edition: 1
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-156116 (URN)9780081020531 (ISBN)9780081020548 (ISBN)
Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-03Bibliographically approved
Stehr, J. E., Chen, W., Shen, S. & Buyanova, I. A. (2018). Effects of N implantation on defect formation in ZnO nanowires. In: : . Paper presented at 20th International Conference on Superlattices, Nanostructures and Nanodevides (ICSNN), Madrid, Spain, July 23-27, 2018..
Open this publication in new window or tab >>Effects of N implantation on defect formation in ZnO nanowires
2018 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-160097 (URN)
Conference
20th International Conference on Superlattices, Nanostructures and Nanodevides (ICSNN), Madrid, Spain, July 23-27, 2018.
Available from: 2019-09-05 Created: 2019-09-05 Last updated: 2019-09-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-7640-8086

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