optical characterization of defects in semiconductors

Abstract

Characterization of deep-level defects in semiconductor materials is at the heart of modern semiconductor science and technology due to their influence in the electronic properties of these materials. Photoluminescence spectroscopy is a powerful technique for the characterization and detailed understanding of the nature of the shallow and deep-level defects in semiconductors. In this project we have carried out experiments using the photoluminescence (PL) technique, providing valuable experience to the research students in the semiconductor physics laboratory and yielding interesting data. It may be added that this marked an exciting new development since it is for the first time in Pakistan that the photoluminescence spectroscopy technique has been introduced. The work carried out under the project consists of following main parts: (a) A detailed PL study was undertaken to characterize the silver defect system in silicon. (b) A detailed photoluminescence investigation of the effects of Al doping on GaAs grown by molecular beam epitaxy (MBE-GaAs) was carried out. Crystals with 0.1%, 1% and 3% Al doping have been studied. Our study on these materials presents results on the optical characteristics of the lowest Al composition GaAs reported to date. (c) Some preliminary investigations have been carried out on the effect of alphairradiation on the photoluminescence properties of both n- and p-type InP.