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| 2. |
- Dagnelund, Daniel, et al.
(författare)
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Effects of hydrogenation on non-radiative defects in GaNP and GaNAs alloys: An optically detected magnetic resonance study
- 2012
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 111:023501
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Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence and optically detected magnetic resonance techniques are utilized to study defect properties of GaNP and GaNAs alloys subjected to post-growth hydrogenation by low-energy sub-threshold ion beam irradiation. It is found that in GaNP H incorporation leads to activation of new defects, which has a Ga interstitial (Ga-i) atom at its core and may also involve a H atom as a partner. The observed activation critically depends on the presence of N in the alloy, as it does not occur in GaP with a low level of N doping. In sharp contrast, in GaNAs hydrogen is found to efficiently passivate Ga-i-related defects present in the as-grown material. A possible mechanism responsible for the observed difference in the H behavior in GaNP and GaNAs is discussed.
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| 3. |
- Dagnelund, Daniel, 1980-, et al.
(författare)
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Evidence for a phosphorus-related interfacial defect complex at a GaP/GaNP heterojunction
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : The American Physical Society. - 1098-0121 .- 1550-235X. ; 81, s. 115334-
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Tidskriftsartikel (refereegranskat)abstract
- Optically detected magnetic resonance (ODMR) studies of molecular beam epitaxial GaNP/GaP structures reveal presence of a P-related complex defect, evident from its resolved hyperfine interaction between an unpaired electronic spin (S=1/2) and a nuclear spin (I = ½) of a 31P atom. The principal axis of the defect is concluded to be along a <111> crystallographic direction from angular dependence of the ODMR spectrum, restricting the P atom (either a PGa antisite or a Pi interstitial) and its partner in the complex defect to be oriented along this direction. The principal values of the electronic g-tensor and hyperfine interaction tensor are determined as: g┴=2.013, g║=2.002, and A┴=130´10-4 cm-1, A║=330´10-4 cm-1, respectively. The interface nature of the defect is clearly manifested by the absence of the ODMR lines originating from two out of four equivalent <111> orientations. Defect formation is shown to be facilitated by nitrogen ion bombardment under non-equilibrium growth conditions and the defect is thermally stable upon post-growth thermal annealing.
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| 4. |
- Lemishko, S. V., et al.
(författare)
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Dielectric resonator in rectangular ??(102) cavity for electron paramagnetic resonance study of thin films
- 2023
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Ingår i: Thin Solid Films. - : ELSEVIER SCIENCE SA. - 0040-6090 .- 1879-2731. ; 768
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Tidskriftsartikel (refereegranskat)abstract
- The improved compared to a rectangular TE(102 )cavity geometry of a dielectric resonator (DR) suitable for studying thin films and coatings has been calculated and experimentally verified. It is shown that electron paramagnetic resonance (EPR) signal of SiOx films can be enhanced by using as the DR of two rectangular parallelepipeds fabricated from BaTi4O9 + 8.5% ZnO ceramics (epsilon=36) with dimension of 5.64x5.5 x 5.9 mm(3 )and a gap of up to 0.5 mm between them. Located inside a standard rectangular metal TE(102 )cavity of the X-band EPR spectrometer, the DR increases the filling factor by 5-12 times depending on the size of a sample studied. The experimental use of the DR allows to increase the EPR signal of the 950 nm SiOx thin film by a factor of approximately 4.
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| 5. |
- Rudko, G.Yu, et al.
(författare)
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Optically detected magnetic resonance study of relaxation/emission processes in the nanoparticle-polymer composite
- 2019
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Ingår i: SPQEO. - Kiev, Ukraine : Natsional'na Akademiya Nauk Ukrainy * Instytut Fizyky Napivprovidnykiv. - 1605-6582. ; 22:3, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 6. |
- Vorona, I.P., et al.
(författare)
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The effect of thermal treatment on radiation-induced EPR signals in tooth enamel
- 2005
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 39:2, s. 137-141
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Tidskriftsartikel (refereegranskat)abstract
- The effect of thermal treatment on the radiation-induced EPR spectrum of tooth enamel was studied. Annealing before sample irradiation was found to increase enamel radiation sensitivity by more than 40%. Depending on the annealing conditions the EPR signals of three supplementary radiation radicals were observed in addition to the main signal caused by CO2¯ radicals. It was found that the presence of these signals in the enamel EPR spectra provides evidence of sample annealing. The possibility of obtaining information about sample history by studying the additional EPR signals is discussed. It can be important to EPR dating and EPR dosimetry. © 2004 Elsevier Ltd. All rights reserved.
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