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Author Spruytte, Sylvia G. ♦ Coldren, Christopher W. ♦ Harris, James S. ♦ Wampler, William ♦ Krispin, Peter ♦ Ploog, Klaus ♦ Larson, Michael C.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword MATERIALS SCIENCE ♦ EFFICIENCY ♦ LATTICE PARAMETERS ♦ LUMINESCENCE ♦ MOLECULAR BEAM EPITAXY ♦ NITROGEN ♦ NUCLEAR REACTION ANALYSIS ♦ ORIGIN ♦ PHOTOELECTRON SPECTROSCOPY ♦ X-RAY DIFFRACTION
Abstract A key to the utilization of nitride-arsenides for long wavelength optoelectronic devices is obtaining low defect materials with long nonradiative lifetimes. Currently, these materials must be annealed to obtain device quality material. The likely defect responsible for the low luminescence efficiency is associated with excess nitrogen. Photoluminescence and capacitance--voltage measurements indicate the presence of a trap associated with excess nitrogen which decreases in concentration upon anneal. Our films are grown by elemental source molecular beam epitaxy and the background impurity concentration is low, thus we have investigated the role of crystalline defects. High resolution x-ray diffraction showed improved crystal quality after anneal. We observed that the lattice parameter does not decrease linearly with nitrogen concentration for levels of nitrogen above 2.9 mol% GaN. The fact that Vegard's law is not observed, despite theoretical calculations that it should, indicates that nitrogen incorporates in locations other than the group V lattice sites. X-ray photoelectron spectroscopy revealed that nitrogen exists in two bonding configurations in not-annealed material: a Ga--N bond and another nitrogen complex in which N is less strongly bonded to gallium atoms. Annealing removes this second nitrogen complex. A combined nuclear reaction analysis and channeling technique showed that not annealed GaNAs contains a significant concentration of interstitial nitrogen that disappears upon anneal. We believe that this interstitial nitrogen is responsible for the deviation from Vegard's law and the low luminescence efficiency of not annealed GaNAs and GaInNAs quantum wells.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-04-15
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 89
Issue Number 8


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