New Materials, Compounds and Applications

The fabrication conditions for CdSe/Cd_1-xMn_xSe thin-film heterojunctions were established. The crystal structure and surface morphology of the thin films were examined. It was found that the Cd_1-xMn_xSe (x = 0.15) thin film crystallizes in a sphalerite-type cubic structure with a lattice parameter of a = 6.05 Å and that Mn atoms are uniformly incorporated into the CdSe lattice without the formation of secondary phases at the microscale. Optical spectra were analyzed and the corresponding band gaps were determined: Eg = 1.74 eV for CdSe and Eg = 1.65 eV for Cd_1-xMn_xSe (x = 0.15). To investigate the current transport mechanism, current-voltage characteristics were measured, including the influence of γ-irradiation on these characteristics. The experiments demonstrated that the I–V behavior of the CdSe/CdMnSe heterojunction varies with the γ-irradiation dose. These changes are primarily attributed to the creation of defects and recombination centers in the crystal lattice induced by irradiation, as well as to a reduction in carrier mobility. Relaxation processes were also studied. The fast relaxation component (τ = 15-35 μs) was associated with intrinsic transitions, whereas the slow relaxation component (τ = 100-200 μs) was related to impurity excitation and exhibited dependence on the irradiation dose. The energy levels of radiation-induced defects responsible for photoconductivity were identified within the range of 0.17-0.22 eV, with defect concentrations on the order of 10¹³-10¹⁵ cm^-3.