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Title: Optical properties of C-doped bulk GaN wafers grown by halide vapor phase epitaxy

Freestanding bulk C-doped GaN wafers grown by halide vapor phase epitaxy are studied by optical spectroscopy and electron microscopy. Significant changes of the near band gap (NBG) emission as well as an enhancement of yellow luminescence have been found with increasing C doping from 5 × 10{sup 16} cm{sup −3} to 6 × 10{sup 17} cm{sup −3}. Cathodoluminescence mapping reveals hexagonal domain structures (pits) with high oxygen concentrations formed during the growth. NBG emission within the pits even at high C concentration is dominated by a rather broad line at ∼3.47 eV typical for n-type GaN. In the area without pits, quenching of the donor bound exciton (DBE) spectrum at moderate C doping levels of 1–2 × 10{sup 17} cm{sup −3} is observed along with the appearance of two acceptor bound exciton lines typical for Mg-doped GaN. The DBE ionization due to local electric fields in compensated GaN may explain the transformation of the NBG emission.
Authors:
; ; ; ;  [1]
  1. Department of Physics, Chemistry, and Biology (IFM), Linköping University, S-581 83 Linköping (Sweden)
Publication Date:
OSTI Identifier:
22402761
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; CATHODOLUMINESCENCE; DOMAIN STRUCTURE; DOPED MATERIALS; ELECTRIC FIELDS; ELECTRON MICROSCOPY; GALLIUM NITRIDES; HALIDES; OPTICAL PROPERTIES; OXYGEN; QUENCHING; SPECTRA; SPECTROSCOPY; VAPOR PHASE EPITAXY