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Raman and transmission electron microscopy characterization of InN samples grown on GaN/Al 2 O 3 by molecular beam epitaxy
Author(s) -
Arvanitidis J.,
Katsikini M.,
Ves S.,
Delimitis A.,
Kehagias Th.,
Komninou Ph.,
Dimakis E.,
Iliopoulos E.,
Georgakilas A.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200565193
Subject(s) - raman spectroscopy , materials science , transmission electron microscopy , molecular beam epitaxy , epitaxy , dislocation , crystallography , microstructure , electron diffraction , lattice constant , diffraction , analytical chemistry (journal) , optics , chemistry , nanotechnology , composite material , physics , layer (electronics) , chromatography
Raman spectroscopy and transmission electron microscopy were employed to study the vibrational properties and the microstructure of epitaxially grown InN films on GaN/Al 2 O 3 templates. The variations of the InN lattice constants, as deduced by electron diffraction analysis, along with the red‐shifted E 2 2 mode frequency reveal that InN films exhibit residual tensile stress, strongly dependent on the epilayer growth temperature. Threading dislocations are the dominant structural defects in the films, having a density in the order of 10 9 –10 10 cm –2 . Profile analysis of the E 2 2 Raman peak by means of the Spatial Correlation Model provides useful information concerning the effective mean length for free phonon propagation ( L ), which is a measure of the structural quality of the samples. In all the studied samples, L monotonically increases with decreasing threading dislocation density of pure screw and mixed type character. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)