Journal article

The atypical temperature evolution of the phonon modes of GaAsN

U Tisch, E Finkman, S Prawer, J Salzman, A Kavokin (ed.), FP Laussy (ed.)

PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 1, NO 6 | WILEY-V C H VERLAG GMBH | Published : 2004

Abstract

We report on the atypical temperature evolution of the phonon modes in undoped, pseudomorphic GaAs1-xNx layers, 0 ≤ x ≤ 4.2%, on GaAs substrates. The modes were characterized by micro-Raman backscattering for temperatures ranging from 90 to 430 K. The dominant Ga-As LO mode of GaAsN is dramatically decreased at 90 K, and intensifies with increasing temperature, in contrast to the expected temperature evolution of first order phonon modes. The TO mode is not Raman active in the zinc blende lattice in the backscattering geometry, but emerges as a result of the symmetry lowering in GaAsN. Both the disorder activated TO mode and the Ga-N local vibrational mode (LVM) are prominent at 90 K, and th..

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