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Title: Angular-dependent Raman study of a- and s-plane InN

Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane (11{sup ¯}20) and semipolar s-plane (101{sup ¯}1) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A{sub 1}(TO), E{sub 1}(TO), and E{sub 2}{sup h} on the angle ψ that corresponds to rotation around the growth axis, is very well reproduced by using expressions taking into account the corresponding Raman tensors and the experimental geometry, providing thus a reliable technique towards assessing the sample quality. The s- and a-plane InN epilayers grown on nitridated r-plane sapphire (Al{sub 2}O{sub 3}) exhibit good crystalline quality as deduced from the excellent fitting of the experimental angle-dependent peak intensities to the theoretical expressions as well as from the small width of the Raman peaks. On the contrary, in the case of the s-plane epilayer grown on non-nitridated r-plane sapphire, fitting of the angular dependence is much worse and can be modeled only by considering the presence of two structural modifications, rotated so as their c-axes are almost perpendicular to each other. Although the presence of the second variant is verified by transmission electron and atomic force microscopies, angular dependent Raman spectroscopy offers a non-destructive and quick way for its quantification.more » Rapid thermal annealing of this sample did not affect the angular dependence of the peak intensities. The shift of the E{sub 1}(TO) and E{sub 2}{sup h} Raman peaks was used for the estimation of the strain state of the samples.« less
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ; ;  [3] ;  [4]
  1. School of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
  2. Chemical Engineering Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
  3. Microelectronics Research Group, Department of Physics, University of Crete, P.O. Box 2208, GR 71003 Heraklion, Greece and IESL, FORTH, P.O. Box 1385, GR 71110 Heraklion (Greece)
  4. Department of Food Technology, Technological Educational Institute of Thessaloniki, 57400 Sindos (Greece)
Publication Date:
OSTI Identifier:
22413141
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; 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; ALUMINIUM OXIDES; ANNEALING; ATOMIC FORCE MICROSCOPY; CRYSTAL GROWTH; ELECTRONS; INDIUM NITRIDES; RAMAN SPECTROSCOPY; ROTATION; SAPPHIRE; STRAINS; TENSORS