Investigation of Free Exciton Properties in GaAs Epitaxial Layer

Abstract

AbstractThe transition energy, the binding energy, the intensity, the broadening and the lifetime of the free-exciton transitions in GaAs epitaxial layer have well been investigated using photoconductivity measurement which is analyzed in term of an improved fitting model. We have found that as the thickness is increased, the bind energy increases, but both the intensity of the high excitonic level and the lifetime of the excitons decrease. These effects are attributed mainly to imperfections located near the surface of the epitaxial layer.