Origin of the red luminescence band in photoluminescence spectra of ZnSe nanowires

In this work, the origin of the deep level, defect related photoluminescence emission band in ZnSe is investigated. Using the dependence of the peak energy on excitation intensity, it was shown to originate from donor-acceptor pair recombination. The binding energy of the donor-acceptor pair was estimated to be 18±0.5meV and the shallow impurity Bohr radius was estimated to be 9.1±0.2nm. Using a postgrowth annealing treatment in a Zn atmosphere, the two species involved in the donor-acceptor pair recombination process were attributed to Zn vacancies and Zn interstitials.