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Title: Anisotropy of effective electron masses in highly doped nonpolar GaN

The anisotropic effective electron masses in wurtzite GaN are determined by generalized infrared spectroscopic ellipsometry. Nonpolar (112{sup ¯}0) oriented thin films allow accessing both effective masses, m{sub ⊥}{sup *} and m{sub ∥}{sup *}, by determining the screened plasma frequencies. A n-type doping range up to 1.7 × 10{sup 20} cm{sup −3} is investigated. The effective mass ratio m{sub ⊥}{sup *}/m{sub ∥}{sup *} is obtained with highest accuracy and is found to be 1.11 independent on electron concentration up to 1.2 × 10{sup 20} cm{sup −3}. For higher electron concentrations, the conduction band non-parabolicity is mirrored in changes. Absolute values for effective electron masses depend on additional input of carrier concentrations determined by Hall effect measurements. We obtain m{sub ⊥}{sup *}=(0.239±0.004)m{sub 0} and m{sub ∥}{sup *}=(0.216±0.003)m{sub 0} for the parabolic range of the GaN conduction band. Our data are indication of a parabolic GaN conduction band up to an energy of approximately 400 meV above the conduction band minimum.
Authors:
; ; ; ; ; ; ; ;  [1]
  1. Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)
Publication Date:
OSTI Identifier:
22253894
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 23; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ACCURACY; DOPED MATERIALS; EFFECTIVE MASS; ELECTRONS; GALLIUM NITRIDES; LANGMUIR FREQUENCY; THIN FILMS