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Title: Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study

Abstract

Cathodoluminescence (CL), electron beam current (EBIC) and transmission electron microscopy (TEM) techniques have been applied to investigate recombination properties and structure of freshly introduced dislocations in low-ohmic GaN crystals. It was confirmed that the only a-screw dislocations exhibited an intense characteristic dislocation-related luminescence (DRL) which persisted up to room temperature and was red-shifted by about 0.3 eV with respect to the band gap energy not only in HVPE but also in MOCVD grown samples. EBIC contrast of the dislocations was found to be temperature independent indicating that the dislocation-related recombination level is situated below 200 meV with respect of conduction band minimum. With the increasing of the magnification of the dislocation TEM cross-sectional images they were found to disappear, probably, due to the recombination enhanced dislocation glide (REDG) under electron beam exposure which was immediately observed in CL investigations on a large scale. The stacking fault ribbon in the core of dissociated a-screw dislocation which form a quantum well for electrons was proposed to play an important role both in DRL spectrum formation and in REDG.

Authors:
;  [1];  [2]; ; ;  [1]; ;  [3]
  1. V.A. Fok Institute of Physics, St. Petersburg State University (Russian Federation)
  2. (Russian Federation)
  3. IV. Physikalisches Institut Georg-August Universität Göttingen (Germany)
Publication Date:
OSTI Identifier:
22609118
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1748; Journal Issue: 1; Conference: STRANN 2016: 5. international conference on state-of-the-art trends of scientific research of artificial and natural nanoobjects, St. Petersburg (Russian Federation), 26-29 Apr 2016; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BEAM CURRENTS; CATHODOLUMINESCENCE; CHEMICAL VAPOR DEPOSITION; CRYSTALS; ELECTRON BEAMS; GALLIUM NITRIDES; QUANTUM WELLS; RECOMBINATION; RED SHIFT; SCANNING ELECTRON MICROSCOPY; SCREW DISLOCATIONS; SPECTRA; STACKING FAULTS; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Medvedev, O. S., E-mail: o.s.medvedev@spbu.ru, Mikhailovskii, V. Yu., IRC for Nanotechnology, Research Park, St.-Petersburg State University, Vyvenko, O. F., Bondarenko, A. S., Ubyivovk, E. V., Peretzki, P., and Seibt, M.. Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study. United States: N. p., 2016. Web. doi:10.1063/1.4954345.
Medvedev, O. S., E-mail: o.s.medvedev@spbu.ru, Mikhailovskii, V. Yu., IRC for Nanotechnology, Research Park, St.-Petersburg State University, Vyvenko, O. F., Bondarenko, A. S., Ubyivovk, E. V., Peretzki, P., & Seibt, M.. Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study. United States. doi:10.1063/1.4954345.
Medvedev, O. S., E-mail: o.s.medvedev@spbu.ru, Mikhailovskii, V. Yu., IRC for Nanotechnology, Research Park, St.-Petersburg State University, Vyvenko, O. F., Bondarenko, A. S., Ubyivovk, E. V., Peretzki, P., and Seibt, M.. Fri . "Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study". United States. doi:10.1063/1.4954345.
@article{osti_22609118,
title = {Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study},
author = {Medvedev, O. S., E-mail: o.s.medvedev@spbu.ru and Mikhailovskii, V. Yu. and IRC for Nanotechnology, Research Park, St.-Petersburg State University and Vyvenko, O. F. and Bondarenko, A. S. and Ubyivovk, E. V. and Peretzki, P. and Seibt, M.},
abstractNote = {Cathodoluminescence (CL), electron beam current (EBIC) and transmission electron microscopy (TEM) techniques have been applied to investigate recombination properties and structure of freshly introduced dislocations in low-ohmic GaN crystals. It was confirmed that the only a-screw dislocations exhibited an intense characteristic dislocation-related luminescence (DRL) which persisted up to room temperature and was red-shifted by about 0.3 eV with respect to the band gap energy not only in HVPE but also in MOCVD grown samples. EBIC contrast of the dislocations was found to be temperature independent indicating that the dislocation-related recombination level is situated below 200 meV with respect of conduction band minimum. With the increasing of the magnification of the dislocation TEM cross-sectional images they were found to disappear, probably, due to the recombination enhanced dislocation glide (REDG) under electron beam exposure which was immediately observed in CL investigations on a large scale. The stacking fault ribbon in the core of dissociated a-screw dislocation which form a quantum well for electrons was proposed to play an important role both in DRL spectrum formation and in REDG.},
doi = {10.1063/1.4954345},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1748,
place = {United States},
year = {Fri Jun 17 00:00:00 EDT 2016},
month = {Fri Jun 17 00:00:00 EDT 2016}
}
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  • No abstract prepared.
  • Using scanning electron microscopy in the cathodoluminescence mode, it is shown that straight segments of a-screw dislocations introduced by plastic deformation at room temperature into unintentionally doped low-resistance gallium nitride luminesce in the spectral range 3.1–3.2 eV at 70 K. The spectral composition of dislocation luminescence shows a fine doublet structure with a component width of ∼15 meV and splitting of ∼30 meV, accompanied by LO-phonon replicas. Luminescent screw dislocations move upon exposure to an electron beam and at low temperatures, but retain immobility for a long time without external excitation. Optical transitions involving the quantum-well states of a stackingmore » fault in a split-dislocation core are considered to be the most probable mechanism of the observed phenomenon.« less