Time-Resolved Studies on Recombination Luminescence of Donor-Acceptor Pairs in ZnSe

Time-resolved studies of luminescence due to the recombination of donor-acceptor pairs in ZnSe are reported. Several sharp luminescence lines were observed under excitation below the band-gap energy, resulting in a determination of the binding energy of the Al donor to be 26.7 meV and that of Na acceptor to be 114 meV. It was also confirmed from analyses of the decay characteristics of the donor-acceptor pair luminescence that the hydrogenic model for energy levels as well as for the Bohr radius holds true for the Al donor. However, for the Na acceptor the Bohr radius which satisfied the experimental decay kinetics should be less than half of the value calculated using the effective-mass approximation.