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Resonant Raman characterization of InAlGaN/GaN heterostructures
Author(s) -
Cros A.,
Cantarero A.,
Pelekanos N. T.,
Georgakilas A.,
Pomeroy J.,
Kuball M.
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.200565132
Subject(s) - phonon , heterojunction , excited state , raman scattering , excitation , absorption edge , materials science , raman spectroscopy , band gap , absorption (acoustics) , condensed matter physics , range (aeronautics) , asymmetry , optoelectronics , atomic physics , optics , physics , quantum mechanics , composite material
InAlGaN/GaN heterostructures and thin films with In composition ranging from 0.03 to 0.1 are characterized by means of Raman scattering excited at various energies in the ultra violet range, tuning the laser excitation energy through the band gap of In x Al y Ga 1– x – y N. It is shown that the addition of In to the Al y Ga 1– y N alloy diminishes considerably the vibration energy of the A 1 (LO) phonon mode. The phonon line is asymmetric on the low energy side, and the asymmetry increases with In content, while the main peak shifts to lower energies. A shift of the phonon energy has also been observed when the excitation energy is close to the absorption edge of the In x Al y Ga 1– x – y N layer. The nature of this shift is discussed in relation with intrinsic and extrinsic inhomogeneities in the quaternary alloy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)