Observation of strain effects and evidence of gallium autodoping in molecular-beam-epitaxial ZnSe on (100)GaAs

Abstract

An analysis of the two-electron satellites of the dominant donor-bound exciton line in photoluminescence of ZnSe layers grown on (100)GaAs by molecular-beam epitaxy indicates that the donor impurity is likely gallium. Strain in the ZnSe epitaxial layers as evidenced by a shift in the positions of the excitonic lines is shown to depend on the growth temperature and is a minimum at about 365 °C. At growth temperatures different from 365 °C the IGa20 line is observed shifted by as much as 3 meV. The relatively small shift of ∼0.4 meV in our layers grown at 365 °C may be due to a strain-relief inelastic process; it is suggested that one possibility might be the formation of a misfit dislocation network at the interface.