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Title: Microscopic potential fluctuations in Si-doped AlGaN epitaxial layers with various AlN molar fractions and Si concentrations

Nanoscopic potential fluctuations of Si-doped AlGaN epitaxial layers with the AlN molar fraction varying from 0.42 to 0.95 and Si-doped Al{sub 0.61}Ga{sub 0.39}N epitaxial layers with Si concentrations of 3.0–37 × 10{sup 17 }cm{sup −3} were investigated by cathodoluminescence (CL) imaging combined with scanning electron microscopy. The spot CL linewidths of AlGaN epitaxial layers broadened as the AlN molar fraction was increased to 0.7, and then narrowed at higher AlN molar fractions. The experimental linewidths were compared with the theoretical prediction from the alloy broadening model. The trends displayed by our spot CL linewidths were consistent with calculated results at AlN molar fractions of less than about 0.60, but the spot CL linewidths were markedly broader than the calculated linewidths at higher AlN molar fractions. The dependence of the difference between the spot CL linewidth and calculated line broadening on AlN molar fraction was found to be similar to the dependence of reported S values, indicating that the vacancy clusters acted as the origin of additional line broadening at high AlN molar fractions. The spot CL linewidths of Al{sub 0.61}Ga{sub 0.39}N epitaxial layers with the same Al concentration and different Si concentrations were nearly constant in the entire Si concentration range tested. Frommore » the comparison of reported S values, the increase of V{sub Al} did not contribute to the linewidth broadening, unlike the case of the V{sub Al} clusters.« less
Authors:
;  [1] ; ;  [2]
  1. Department of Material Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, Yamaguchi 755-8611 (Japan)
  2. Department of Electrical and Electronic Engineering, Mie University, 1577 Kurimamachiya, Tsu, Mie 514-8507 (Japan)
Publication Date:
OSTI Identifier:
22494918
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 2; Other Information: (c) 2016 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; ALUMINIUM NITRIDES; CATHODOLUMINESCENCE; CONCENTRATION RATIO; DOPED MATERIALS; EPITAXY; FLUCTUATIONS; LAYERS; LINE BROADENING; LINE WIDTHS; POTENTIALS; SCANNING ELECTRON MICROSCOPY; VACANCIES