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Title: Dielectric functions and carrier concentrations of Hg{sub 1−x}Cd{sub x}Se films determined by spectroscopic ellipsometry

Spectroscopic ellipsometry, ranging from 35 meV to 6 eV, was used to determine the dielectric functions of a series of molecular beam epitaxy-grown Hg{sub 1−x}Cd{sub x}Se thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates. The fundamental band gap as well as two higher-order electronic transitions blue-shift with increasing Cd composition in Hg{sub 1−x}Cd{sub x}Se, as expected. Representing the free carrier absorption with a Drude oscillator, we found that the effective masses of Hg{sub 1−x}Cd{sub x}Se (grown on ZnTe/Si) vary between 0.028 and 0.050 times the free electron mass, calculated using the values of carrier concentration and the mobility obtained through Hall measurements. Using these effective masses, we determined the carrier concentrations of Hg{sub 1−x}Cd{sub x}Se samples grown on GaSb, which is of significance as films grown on such doped-substrates posit ambiguous results when measured by conventional Hall experiments. These models can serve as a basis for monitoring Cd-composition during sample growth through in-situ spectroscopic ellipsometry.
Authors:
;  [1] ; ;  [2] ;  [3]
  1. Department of Physics, Kenyon College, Gambier, Ohio 43022 (United States)
  2. U.S. Army Research Laboratory, Adelphi, Maryland 20783-1197 (United States)
  3. Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)
Publication Date:
OSTI Identifier:
22489110
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 7; 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AUGMENTATION; CARRIERS; CONCENTRATION RATIO; DIELECTRIC MATERIALS; DOPED MATERIALS; ELLIPSOMETRY; EV RANGE 01-10; GALLIUM ANTIMONIDES; MILLI EV RANGE; MOBILITY; MOLECULAR BEAM EPITAXY; OSCILLATORS; SUBSTRATES; THIN FILMS; ZINC TELLURIDES