Synthesis, Structure and Electro-Physical Properties n-GaAs–p-(GaAs)_{1 –x–y}(Ge₂)_x(ZnSe)_y Heterostructures (Review)

A review of experimental and theoretical studies on technology for producing the single-crystal substitutional solid solution of p-(GaAs)_{1 – x – y}(Ge₂)_x(ZnSe)_y on (GaAs) with the given crystallographic orientation using the liquid-phase epitaxy method is presented in this paper. The methods for determining the optimal parameters of the grown epitaxial films are given. Based on the analysis of literature data and the experimental results of the authors, the optimal parameters of epitaxial films are established. The solid solutions (GaAs)_0.69(Ge₂)_0.17(ZnSe)_0.14 have a sphalerite structure and possible configurations of the arrangement of atoms and molecules are determined. It has been established that paired Ge atoms partially replace GaAs molecules in the defective regions of the matrix lattice, and zinc selenide molecules form nanoislands on the surface layer of the GaAs_1 – xGe_x solid solution, which have the geometric shape dome, with lateral dimensions of 55–65 nm. Research investigating current transfer mechanisms in n-GaAs–p-(GaAs)_{1 – x – y}(Ge₂)_x(ZnSe)_y hetero-structures at room temperature show that in the voltage range from 0.7 to 3 V degree depends J = АV^α (α₁ = 2, α₂ = 2.7 and α₃ = 3) are observed, which arise due to the formation of complex recombination complexes. The noticeable photosensitivity of n-GaAs–p-(GaAs)_0.69(Ge₂)_0.17(ZnSe)_0.14 hetero-structure begins at the photon energy of 1.16 eV, and the maximum is observed at the photon energy of 1.38 eV. In the short-wave region of the emission spectrum, peaks are observed with maxima at photon energies of 1.37, 1.47, 1.65, 1.88, 2.3, and 2.62 eV, as well as the gentle portion at 2.26–2.46 eV. Analysis using the Gaussian approximation showed that these features of the photo-spectrum are related to the state of the atoms of the constituent components and their interaction when illuminated by sunlight. It has been established that heterostructures have the property of controlled selective photosensitivity.