Premium
Disorder‐Activated Scattering and Two‐Mode Behavior in Raman Spectra of Isotopic GaN and AlGaN
Author(s) -
Wieser N.,
Ambacher O.,
Angerer H.,
Dimitrov R.,
Stutzmann M.,
Stritzker B.,
Lindner J.K.N.
Publication year - 1999
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/(sici)1521-3951(199911)216:1<807::aid-pssb807>3.0.co;2-c
Subject(s) - raman spectroscopy , raman scattering , materials science , molecular vibration , ion , isotopic shift , epitaxy , normal mode , isotope , analytical chemistry (journal) , kinetic isotope effect , molecular physics , vibration , chemistry , atomic physics , optics , nanotechnology , physics , deuterium , organic chemistry , layer (electronics) , quantum mechanics , chromatography
Micro‐Raman spectroscopy has been applied to isotopically pure Ga i N ( i = 14, 15) epitaxial films in which structural disorder was introduced by ion implantation or mechanical damage. A pair of Raman peaks appearing at about 300 (300) and 667 (646) cm —1 is consistent with the anion mass 14 (15) suggesting disorder activation of the silent B 1 modes, where the low‐frequency mode is related to the Ga vibration (no N isotope shift) and the high‐frequency mode to the N vibration (full N isotope shift). Isotopically pure Al 0.5 Ga 0.5 i N indicates respective activation of the silent B 1 modes due to alloying disorder and confirms a two‐mode behavior of the E 2 mode. In agreement with recent IR measurements and theoretical predictions, we additionally provide evidence for an E 1 (TO) two‐mode behavior in Raman scattering as obtained from polarisation dependent measurements on Al x Ga 1— x N epilayers.