Optical Absorption Edge in GaSe under Hydrostatic Pressure

Abstract

A study of the optical absorption spectrum of GaSe at the energy gap shows that the strength of the exciton line decreases as hydrostatic pressure is increased. It is proposed that this effect comes from increasing interference of the discrete exciton line with a continuum of structure due to indirect interband electronic transitions. The sign and magnitude of the pressure coefficients of the gaps in gallium chalcogenides are found to be consistent with recent band-structure studies.