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Title: Temperature dependent dielectric function and the E{sub 0} critical points of hexagonal GaN from 30 to 690 K

The complex dielectric function ε and the E{sub 0} excitonic and band-edge critical-point structures of hexagonal GaN are reported for temperatures from 30 to 690 K and energies from 0.74 to 6.42 eV, obtained by rotating-compensator spectroscopic ellipsometry on a 1.9 μm thick GaN film deposited on a c-plane (0001) sapphire substrate by molecular beam epitaxy. Direct inversion and B-splines in a multilayer-structure calculation were used to extract the optical properties of the film from the measured pseudodielectric function 〈ε〉. At low temperature sharp E{sub 0} excitonic and critical-point interband transitions are separately observed. Their temperature dependences were determined by fitting the data to the empirical Varshni relation and the phenomenological expression that contains the Bose-Einstein statistical factor.
Authors:
; ; ; ; ;  [1]
  1. Nano-Optical Property Laboratory and Department of Physics, Kyung Hee University, Seoul 130-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22251230
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 2; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DEPOSITS; DIELECTRIC MATERIALS; ELLIPSOMETRY; FILMS; GALLIUM NITRIDES; MOLECULAR BEAM EPITAXY; OPTICAL PROPERTIES; SAPPHIRE; SUBSTRATES; TEMPERATURE DEPENDENCE