Gavaleshko O. Zinc selenide heterolayers for solid-state optoelectronic devices

The dissertation is devoted to the development of the radiation layers of zinc selenide in short-wave region of the optical range, obtained by the method of isovalent substitution. The method was developed, optimal regimes were determined and heterolayers α- and β-ZnSe were obtained. For the first time, the basic parameters of the energy structure α-ZnSe Δcr = 0,07 eV and Δso = 0,37 eV were determined. The optical processes of absorption, reflection and photoluminescence of the heterolayers were investigated, their properties, characteristics and parameters were determined. It has been established that the method of isovalent substitution allows to obtain an ultrasound laser with intense luminescence in the short-wave region of the optical range λ = 0,36÷0,52 μm in accordance with the modification of the α- and β-crystalline lattice. It is formed by a dominant process of annihilation of bound excitons in an isovalent impurity and interband recombination of free charge carriers. The high quantum efficiency η = 8÷12 %, the weak temperature dependence of the intensity, position of the maximum of radiation, the time stability and repeatability of the characteristics are inherent to obtained α- and β-ZnSe. That can be used in different types of sensors when registering the temperature. For the first time, the stability of the luminescence properties of α-ZnSe has been established prior to irradiation by an electron beam of density D  7,51015 electron/cm2 with an energy of E ~ 2 MeV. The modes of obtained α-ZnSe layers on α-CdSe with different luminescence spectrum in the range from λm = 0,43 μm to λm = 0,51 μm are established. The short-wave optical radiation in the near-ultraviolet region with photon energy ћωm = 3,05-3,30 eV with a maximum of ћωm = 3,18 eV and a quantum efficiency η = 5,8% at 300 K on the ZnSexS1-x heterolayer is obtained. Solid solutions are obtained on α-CdS by successive diffusion of Zn and Se at T = 1100÷1500 K. Radiation with a maximum ћωm = 3,24 eV and η = 15% efficiency is obtained on a modified surface of α-ZnSe. Characteristics and properties are determined by the dimensional quantization of the energy of charge carriers due to the formation of nanostructure.