Specific features of the optical and electrical properties of polycrystalline CdTe films grown by the thermal evaporation method

The results of studying the physical properties of thin CdTe films obtained by the thermal evaporation method have been presented. The optical constants and the band gap of the films under study have been determined ($E_g$ = 1.46 eV). It has been established based on the investigation of optical properties and the Raman spectrum of the films that they possess high structural quality. The activation energy of the electrical conductivity of CdTe films has been determined: $E_a$ = 0.039 eV. The measured spectral dependences of the impedance of CdTe thin films are characteristic of the inhomogeneous medium with two time constants: $\tau_{\mathrm{gb}} = R_{\mathrm{gb}}C_{\mathrm{gb}} = 1/\omega_{\mathrm{gb}}$ = 1.62 $\times$ 10$^{-3}$ s and $\tau_{\mathrm{g}} = R_{\mathrm{g}}C_{\mathrm{g}} = 1/\omega_{\mathrm{g}}$ = 9.1 $\times$ 10$^{-7}$ s for grain boundaries and grains, respectively.