PHOTOLUMINESCENCE OF DONOR-DOPED ZNSE FILMS GROWN BY MOLECULAR-BEAM EPITAXY

We studied the effect of the donor doping of ZnSe films on their photo luminescence properties. The samples were doped during the molecular b eam epitaxy growth, either with gallium or with chlorine. As the dopan t concentration dose increases, the intensity of the band-edge emissio n first saturates, and then quenches in favor of the deep-level photol uminescence band. The main effect of donor doping on photoluminescence is a strong increase in intensity of the donor-bound exciton line, re ferred to as It. For Ga-doped films deep-band emission is much stronge r, and the I-2-line is slightly weaker than for Cl-doped films with co mparable doping level. The results confirm the superiority of chlorine over gallium as an n-type dopant in ZnSe. We discuss the photolumines cence results and relate them to deep level transient spectroscopy dat a obtained on the same samples.