Anomalous Edge Emission from Zinc Selenide Heavily Doped with Oxygen

The specific features of the emission spectra of pure chemical-vapor deposited (CVD) ZnSe condensates grown with an excess of selenium and with doping with oxygen are studied. The anomalous 477(490)-nm edge emission prevailing in the low-temperature cathodoluminescence spectra of ZnSe(O) is studied in order to elucidate the nature of this emission. The relation of this emission to the stoichiometry composition of ZnSe and to the concentration of dissolved oxygen is established. The data suggesting the role of the copper impurity are obtained. On the basis of the band-anticrossing theory, a band model is developed to interpret the nature of the basic luminescence bands of ZnSe(O) and ZnSe(O,Cu) in the near-edge spectral region. It is shown that the model for ZnSe(O) is similar to the model previously proposed for ZnS(O) and CdS(O).