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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)
Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-10-10Bibliographically approved
Zhang, P., Sadeghimeresht, E., Chen, S., Li, X.-H., Markocsan, N., Joshi, S., . . . Peng, R. L. (2019). Effects of Surface Finish on the Initial Oxidation of HVAF-sprayed NiCoCrAlY Coatings. Surface & Coatings Technology, 364, 43-56
Open this publication in new window or tab >>Effects of Surface Finish on the Initial Oxidation of HVAF-sprayed NiCoCrAlY Coatings
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2019 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Journal of Surface and Coatings Technology, ISSN 0257-8972, Vol. 364, p. 43-56Article in journal (Refereed) Published
Abstract [en]

Oxide scale formed on HVAF-sprayed NiCoCrAlY coatings and the effect of surface treatment were investigated by a multi-approach study combining photo-stimulated luminescence, microstructural observation and mass gain. The initial oxidationbehaviour of as-sprayed, polished and shot-peened coatings at 1000 °C is studied. Both polished and shot-peened coatings exhibited superior performance due to rapid formation of α-Al2O3 fully covering the coating and suppressing the growth of transient alumina, assisted by a high density of α-Al2O3 nuclei on surface treatment induced defects. Moreover, the fast development of a two-layer alumina scale consisting of an inward-grown inner α-Al2O3 layer and an outer layer transformed from outward-grown transient alumina resulted in a higher oxide growth rate of the as-sprayed coating.

Place, publisher, year, edition, pages
Elsevier: Elsevier, 2019
Keywords
Oxidation, Transient ot alpha transformation, Surface treatment, Polishing, Shot-peening, Photo-stimulated liminescence spectroscopy
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-154936 (URN)10.1016/j.surfcoat.2019.02.068 (DOI)000463302800006 ()2-s2.0-85062231529 (Scopus ID)
Note

Funding agencies: Siemens Industrial Turbomachinery AB (Finspang, Sweden) [KME-703]; Swedish Energy Agency through KME consortium [KME-703]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00

Available from: 2019-03-06 Created: 2019-03-06 Last updated: 2019-06-28Bibliographically 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., 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
Goransson, D. J., Borgstrom, M. T., Huang, Y., Messing, M. E., Hessman, D., Buyanova, I. A., . . . Xu, H. Q. (2019). Measurements of Strain and Bandgap of Coherently Epitaxially Grown Wurtzite InAsP-InP Core-Shell Nanowires. Nano letters (Print), 19(4), 2674-2681
Open this publication in new window or tab >>Measurements of Strain and Bandgap of Coherently Epitaxially Grown Wurtzite InAsP-InP Core-Shell Nanowires
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2019 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, no 4, p. 2674-2681Article in journal (Refereed) Published
Abstract [en]

We report on experimental determination of the strain and bandgap of InAsP in epitaxially grown InAsP-InP core-shell nanowires. The core-shell nanowires are grown via metal-organic vapor phase epitaxy. The as-grown nanowires are characterized by transmission electron microscopy, X-ray diffraction, micro-photoluminescence (mu PL) spectroscopy, and micro-Raman (mu-Raman) spectroscopy measurements. We observe that the core-shell nanowires are of wurtzite (WZ) crystal phase and are coherently strained with the core and the shell having the same number of atomic planes in each nanowire. We determine the predominantly uniaxial strains formed in the core-shell nanowires along the nanowire growth axis and demonstrate that the strains can be described using an analytical expression. The bandgap energies in the strained WZ InAsP core materials are extracted from the mu PL measurements of individual core-shell nanowires. The coherently strained core-shell nanowires demonstrated in this work offer the potentials for use in constructing novel optoelectronic devices and for development of piezoelectric photovoltaic devices.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
Strain; core-shell nanowire; wurtzite; InAsP; InP; mu PL; mu-Raman
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-157241 (URN)10.1021/acs.nanolett.9b00644 (DOI)000464769100066 ()30908918 (PubMedID)2-s2.0-85064175484 (Scopus ID)
Note

Funding Agencies|Myfab; Swedish Research Council (VR); Ministry of Science and Technology of China through the National Key Research and Development Program of China [2017YFA0303304, 2016YFA0300601]; National Natural Science Foundation of China [11874071, 91221202, 91421303]

Available from: 2019-06-13 Created: 2019-06-13 Last updated: 2019-06-18Bibliographically 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: 2019-10-10Bibliographically approved
Li, Z., Sun, H., Hsiao, C.-L., Yao, Y., Xiao, Y., Shahi, M., . . . Zhang, F. (2018). A Free-Standing High-Output Power Density Thermoelectric Device Based on Structure-Ordered PEDOT:PSS. Advanced Electronic Materials, 4(2), Article ID 1700496.
Open this publication in new window or tab >>A Free-Standing High-Output Power Density Thermoelectric Device Based on Structure-Ordered PEDOT:PSS
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2018 (English)In: Advanced Electronic Materials, ISSN 2199-160X, Vol. 4, no 2, article id 1700496Article in journal (Refereed) Published
Abstract [en]

A free-standing high-output power density polymeric thermoelectric (TE) device is realized based on a highly conductive (approximate to 2500 S cm(-1)) structure-ordered poly(3,4-ethylenedioxythiophene):polystyrene sulfonate film (denoted as FS-PEDOT:PSS) with a Seebeck coefficient of 20.6 mu V K-1, an in-plane thermal conductivity of 0.64 W m(-1) K-1, and a peak power factor of 107 mu W K-2 m(-1) at room temperature. Under a small temperature gradient of 29 K, the TE device demonstrates a maximum output power density of 99 +/- 18.7 mu W cm(-2), which is the highest value achieved in pristine PEDOT:PSS based TE devices. In addition, a fivefold output power is demonstrated by series connecting five devices into a flexible thermoelectric module. The simplicity of assembling the films into flexible thermoelectric modules, the low out-of-plane thermal conductivity of 0.27 W m(-1) K-1, and free-standing feature indicates the potential to integrate the FS-PEDOT:PSS TE modules with textiles to power wearable electronics by harvesting human bodys heat. In addition to the high power factor, the high thermal stability of the FS-PEDOT:PSS films up to 250 degrees C is confirmed by in situ temperature-dependent X-ray diffraction and grazing incident wide angle X-ray scattering, which makes the FS-PEDOT:PSS films promising candidates for thermoelectric applications.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
free-standing PEDOT:PSS film; output power density; p-type; thermoelectric generators
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-145465 (URN)10.1002/aelm.201700496 (DOI)000424888600015 ()2-s2.0-85039784826 (Scopus ID)
Note

Funding Agencies|Vinnova Marie Curie incoming project [2016-04112]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [200900971]; Recruitment Program of Global Youth Experts; National Natural Science Foundation of China [21474035]; United States National Science Foundation [DMR-1262261]; Open Fund of the State Key Laboratory of Luminescent Materials and Devices [2016-skllmd-03]; European Research Council [ERC 307596]

Available from: 2018-03-13 Created: 2018-03-13 Last updated: 2018-04-09Bibliographically approved
Chen, W. & Buyanova, I. (2018). Defect-enabled room-temperature spin functionalities in a non-magnetic semiconductor. In: Jan Stehr. Irina Buyanova & Weimin Chen (Ed.), Defects in Advanced Electronic Materials and Novel Low Dimensional Structures: (pp. 265-284). Woodhead Publishing Limited
Open this publication in new window or tab >>Defect-enabled room-temperature spin functionalities in a non-magnetic semiconductor
2018 (English)In: Defects in Advanced Electronic Materials and Novel Low Dimensional Structures / [ed] Jan Stehr. Irina Buyanova & Weimin Chen, Woodhead Publishing Limited, 2018, p. 265-284Chapter in book (Refereed)
Abstract [en]

Departing from common methods of employing magnetic materials, generation of spin-polarized electrons in a semiconductor mediated by spin-dependent processes via defects represents an unconventional approach without invoking magnetism. Here, we provide a brief description of the physical principle and review our recent work on exploring this unconventional approach to achieve desired spin functionalities in nonmagnetic semiconductors without requiring a magnetic layer or an external magnetic field. We demonstrate that fundamental spin functionalities such as spin filtering, spin amplification and spin detection can be achieved at room temperature (RT). By combining the spin-filtering effect and electron–nuclear spin interaction, we also show that efficient nuclear spin hyperpolarization of a defect atom in a semiconductor can be realized at RT via spin-polarized conduction electrons. Such approaches could potentially lead to development of basic spintronic components that serve as building blocks in future spintronics and spin-photonics, thereby providing an attractive solution to the current and important problems in room-temperature spin-functional semiconductors.

Place, publisher, year, edition, pages
Woodhead Publishing Limited, 2018
Keywords
spin filtering; spin amplification; spin detection; dynamic nuclear spin polarization; defect; non-magnetic semiconductor; dilute nitride; GaNAs; GaInNAs; spin-dependent recombination
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-160781 (URN)10.1016/B978-0-08-102053-1.00011-9 (DOI)9780081020531 (ISBN)9780081020548 (ISBN)
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically 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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6405-9509

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