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Title: Fine structure of the red luminescence band in undoped GaN

Many point defects in GaN responsible for broad photoluminescence (PL) bands remain unidentified. Their presence in thick GaN layers grown by hydride vapor phase epitaxy (HVPE) detrimentally affects the material quality and may hinder the use of GaN in high-power electronic devices. One of the main PL bands in HVPE-grown GaN is the red luminescence (RL) band with a maximum at 1.8 eV. We observed the fine structure of this band with a zero-phonon line (ZPL) at 2.36 eV, which may help to identify the related defect. The shift of the ZPL with excitation intensity and the temperature-related transformation of the RL band fine structure indicate that the RL band is caused by transitions from a shallow donor (at low temperature) or from the conduction band (above 50 K) to an unknown deep acceptor having an energy level 1.130 eV above the valence band.
Authors:
 [1] ;  [2] ;  [3] ; ;  [2]
  1. Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)
  2. Nitride Crystals, Inc., 181E Industry Ct., Ste. B, Deer Park, New York 11729 (United States)
  3. (Russian Federation)
Publication Date:
OSTI Identifier:
22280620
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ELECTRONIC STRUCTURE; ENERGY LEVELS; EXCITATION; FINE STRUCTURE; GALLIUM NITRIDES; HYDRIDES; LAYERS; PHASE TRANSFORMATIONS; PHONONS; PHOTOLUMINESCENCE; POINT DEFECTS; TEMPERATURE DEPENDENCE; VALENCE; VAPOR PHASE EPITAXY