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Author Zhang, Yong ♦ Mascarenhas, A. ♦ Xin, H. P. ♦ Tu, C. W.
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 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ALLOYS ♦ BOUND STATE ♦ IMPURITIES ♦ NITROGEN
Abstract The band-gap reduction caused by heavy impurity doping in a semiconductor can be written as {delta}E{sub g}(x){proportional_to}x{sup {alpha}}, where x is the mole fraction of the impurities, and {alpha} is the scaling exponent. It is well known that {alpha}=1/3 for n- or p-type (i.e., charged) doping, where the isolated impurity center forms bound states. In contrast, the incorporation of isoelectronic impurities into a semiconductor commonly results in alloy formation. In this case, the impurities do not form any bound states (with small cluster sizes), and one finds that {alpha}=1. However, for the case of nitrogen doping in GaAs, although isolated nitrogen impurities do not form bound states, nitrogen impurity pairs do, and we find {alpha}=2/3. The scaling rule revealed here demonstrates that the dominant mechanism for the large band-gap reduction observed in GaAs{sub 1-x}N{sub x} is the formation of an impurity band associated with nitrogen pair bound states.
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-04-15
Publisher Place United States
Journal Physical Review B
Volume Number 63
Issue Number 16


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