Electrical properties of ZnSe crystals doped with transition elements

The conductivity and photoconductivity of ZnSe crystals doped with transition elements are studied. It is shown that the doping of ZnSe crystals with 3$d$ impurity elements is not accompanied by the appearance of electrically active levels of these impurities. At the same time, the introduction of these impurities into the cation sublattice brings about the formation of electrically active intrinsic defects. It is established that ZnSe crystals doped with Ti, V, Cr, Fe, Co, or Ni exhibit high-temperature impurity photoconductivity. Photoconductivity mechanisms in the crystals are proposed. From the position of the first ionization photoconductivity band, the energies of ground states of 3$d^{2+}$ ions in ZnSe crystals are determined.