Heterolayers of Hexagonal α-CdTe

The importance of the direct band structure of CdTe as a necessary condition for the creation of high-performance photoelectronic devices based on it is argued. The possibility of obtaining heterolayers (HLs) of cadmium tellurides by the method of isovalent substitution is shown. Prerequisites for manufacturing are determined and technological modes of isothermal annealing of -CdSe and -CdS base crystals are developed. For the first time, HLs with a little-used atypical hexagonal modification -CdTe crystal lattice with highly stable properties are obtained by isovalent substitution. A technique is developed, and the basic parameters of the band structure and luminescence characteristics are studied by the method of -modulation of optical irradiation. The band gap Eg  1.56 eV is established, and the parameters of the band structure are determined for the first time, namely, the subbands of the valence band split off due to the action of the crystal field Δcr ≈ 0.06 eV and the spin-orbit interaction Δso ≈ 0.38 eV. A high quantum efficiency  ≈ 7-9 % of the dominant radiation in the edge region is established. It is determined by doping with isovalent impurities, which are the atoms of the base substrate. An important prerequisite for obtaining high intensity (compared to CdTe crystals with  ~ 0.1-0.2 %) is the formation of a transition layer of the corresponding solid solution between the components of heterostructures, which significantly reduces the concentration of defects and the discrepancy between the crystalline and thermal parameters of the contacting materials. The obtained features of the crystal structure provide the conditions for the formation of effective luminescence, the basic mechanisms of which are interband radiative transitions and the dominant annihilation of excitons bound on isovalent impurities.