Effect of iron impurities on the photoluminescence and photoconductivity of ZnSe crystals in the visible spectral region

The photoconductivity and photoluminescence of ZnSe:Fe crystals in the visible spectra region are studied. The scheme of optical transitions within Fe2+ impurity centers is established. It is shown that the high-temperature photoconductivity of ZnSe:Fe crystals is controlled by optical transitions of electrons from the 5E(F) ground state to the higher levels of excited states of Fe2+ ions, with subsequent thermal activation of the electrons to the conduction band. Efficient excitation of intracenter luminescence of ZnSe:Fe crystals is attained with light corresponding to the region of intrinsic absorption in Fe2+ ions.