The photoluminescence spectrum of bound excitons in indium phosphide and gallium arsenide

Abstract

Photoluminescence spectra of refined epitaxial indium phosphide and gallium arsenide show clearly a close correspondence of bound exciton transitions. Classified in both materials are emissions due to excitons bound to neutral acceptors and donors, free exciton peaks and various types of phonon coupling. Excitons bound to neutral acceptors in both materials give rise to a sharp doublet emission which readily reveals the presence of strain in the sample. The magnitude of the strain is estimated to be approximately 10-3 in certain regions of typical epitaxial layers. Reflectivity experiments provide new estimates of the exciton gaps-1.4182 eV in indium phosphide and 1.5150 eV in gallium arsenide.