Photoluminescence investigation of the band around 1.41 eV in heated <i>n</i>-GaAs samples

Abstract

This paper deals with the nature and origin of the ∼1.41-eV emission band observed in the photoluminescence (PL) spectra of n-GaAs samples subjected to diverse treatments. An investigation of the defect center responsible for this emission is carried by performing PL measurements on several samples (n substrates and n/n+ epilayers) subjected to two types of heat treatments (’’preepigrowth’’ and ’’open tube’’) at different temperatures and under varied conditions of surface protection. In light of the different experimental results we propose that the defect under consideration is a complex center formed by the association of arsenic vacancies and Si atoms (SiAs). Also, the existence of this defect in undoped epilayers grown on heavily silicon-doped substrates by the LPE technique, is tentatively explained as due to the contribution of the substrate during the epiprocess.