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Raman Frequencies and Angular Dispersion of Polar Modes in Aluminum Nitride and Gallium Nitride
Author(s) -
Filippidis L.,
Siegle H.,
Hoffmann A.,
Thomsen C.,
Karch K.,
Bechstedt F.
Publication year - 1996
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.2221980207
Subject(s) - wurtzite crystal structure , pseudopotential , materials science , gallium nitride , raman spectroscopy , raman scattering , polar , dispersion (optics) , phonon , wide bandgap semiconductor , optics , transverse plane , nitride , molecular physics , condensed matter physics , optoelectronics , physics , nanotechnology , zinc , structural engineering , engineering , layer (electronics) , astronomy , metallurgy
Abstract We performed angular‐resolved Raman‐scattering experiments on AlN and GaN both grown in the wurtzite structure. Our measurements reveal that the transverse polar modes in AlN and GaN show a pronounced angular dispersion. We varied the angle between the phonon‐propagation direction and the optical axis between 41° and 90° and observed a frequency shift of the A 1 (TO) mode in the range of 28 cm −1 in AlN and of 15 cm −1 in GaN. The experimental values agree well with our theoretical calculations which were carried out using the DFT‐LDA plane‐wave pseudopotential method.