RAMAN-SCATTERING PROBE OF ANHARMONIC EFFECTS DUE TO TEMPERATURE AND COMPOSITIONAL DISORDER IN III-V BINARY AND TERNARY ALLOY SEMICONDUCTORS

Anharmonicity due to temperature and compositional fluctuations in ter nary alloy semiconductors has been investigated. A comparative Raman-s cattering study of temperature and compositional-fluctuation-induced a nharmonic effects for various phonon modes in GaP, GaAs1-xPx, and InxG a1-xAs is presented. In binary semiconductors, anharmonicity is found to increase with increasing temperature, whereas, in ternary alloys, i t is found to increase with increasing compositional fluctuations and increasing temperature. Temperature-induced anharmonicity introduces c hanges in the linewidth and line center position, while compositional- fluctuation-induced anharmonicity, not only introduces changes in the linewidth and line center position, but also changes the line shape.