Raman scattering study of photoluminescent spark-processed porous InP

Abstract

Raman scattering has been used to study porous InP 001. samples prepared by the application of high voltage spark discharges in air and argon atmospheres. For photoluminescent material, Raman scattering as well as Normaski microscopy of a transversally cut sample, 011. face, show the existence of two very distinct zones, that lie at different depths: a superficial luminescent region constituted mostly by In2O3 and InPO4 oxides, and a second adjacent deeper zone formed by damaged InP. These results highlight the role that the oxidation plays in this material as source of the visible luminescence that the material emits when excited with UV radiation. The deepest region shows InP-like vibrational behavior with broad longitudinal optical LO. and transversal optical TO. phonon bands. A fit of the observed lineshapes of the TO and LO modes using the spatial correlation model provides an estimate of the size of the crystalline regions L;30 A°.. Q 2000 Elsevier Science B.V. All rights reserved.