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Title: Band gap bowing parameter in pseudomorphic Al{sub x}Ga{sub 1−x}N/GaN high electron mobility transistor structures

A method for evaluation of aluminium composition in pseudomorphic Al{sub x}Ga{sub 1−x}N layer from the measured photoluminescence (PL) peak energy is presented here. The layers were grown by metalorganic chemical vapor deposition and characterized by high resolution X-ray diffraction (HRXRD), PL, cathodoluminescence, and atomic force microscopy. We estimated the value of biaxial stress in pseudomorphic Al{sub x}Ga{sub 1−x}N layers grown on sapphire and silicon carbide substrates using HRXRD scans. The effect of biaxial stress on the room temperature band edge luminescence in pseudomorphic Al{sub x}Ga{sub 1−x}N/GaN layers for various aluminium compositions in the range of 0.2 < x < 0.3 was determined. The value of pressure coefficient of band gap was also estimated. The stress corrected bowing parameter in Al{sub x}Ga{sub 1−x}N was determined as 0.50 ± 0.06 eV. Our values match well with the theoretically obtained value of bowing parameter from the density functional theory.
Authors:
; ; ; ; ;  [1]
  1. Solid State Physics Laboratory, Lucknow Road, Delhi 110054 (India)
Publication Date:
OSTI Identifier:
22412938
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 22; Other Information: (c) 2015 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; ALUMINIUM COMPOUNDS; ATOMIC FORCE MICROSCOPY; CATHODOLUMINESCENCE; CHEMICAL VAPOR DEPOSITION; CONCENTRATION RATIO; DENSITY FUNCTIONAL METHOD; ELECTRON MOBILITY; ELECTRONIC STRUCTURE; ENERGY GAP; GALLIUM NITRIDES; LAYERS; PHOTOLUMINESCENCE; SAPPHIRE; SILICON CARBIDES; STRESSES; SUBSTRATES; TRANSISTORS; X-RAY DIFFRACTION