Modification of Optical Properties of Porous AIIIBV Layers Produced by Anodic Etching

Abstract

Morphology investigations (atomic force microscopy (AFM) and scanning electron microscopy (SEM)), study of Raman scattering (RS) and photoluminescence (PL) have been performed to characterize a series of AIIIBV materials (GaAs, GaP, InP) with an electrochemically prepared porous surface layer. It has been shown that the surface morphology of porous AIIIBV compounds strongly depends on various parameters of the anodizationprocess such as the etching time, current density, composition of etching solution, and illumination during the etching procedure. The enhancement of a Raman signal from porous surfaces, which has been observed for almost all samples, is caused mainly by the breaking of selection rules for corresponding phonon modes and a decrease of the reflection at the porous surface. The peculiarities of the PL spectra of porous AIIIBV compounds are studied in a wide temperature range. The small quantum confinement effect has been observed for GaAs and InP porous surfaces.