Electron diffraction study of phase formation in nano layers of Cu$_2$Te–In$_2$Te$_3$, Cu–In–Te systems and short-range atomic order in amorphous CuIn$_5$Te$_8$

It is shown that with the simultaneous and sequential deposition of films of the Cu$_2$Te–In$_2$Te$_3$ system, as well as copper, indium, and tellurium of the highest purity used as starting materials, $\sim$99.999%, taken in the ratio Cu : In : Te = 1 : 5 : 8, regardless of the deposition order ternary compounds of the compositions CuInTe$_2$, CuIn$_3$Te$_5$, and CuIn$_5$Te$_8$ in the crystalline state are distinguished. During vacuum condensation of films on single-crystal substrates NaCl, KCl and amorphous celluloid cooled by liquid nitrogen to 203 K, the resulting films obtained both by co-evaporation of binary compounds of the Cu$_2$Te–In$_2$Te$_3$ system and by the synthesis of thin layers applied by Cu, In, Te are amorphous. For the first time in nanosized amorphous films of the composition CuIn$_5$Te$_8$, crystallizing in the tetragonal system with the periods of unit cells $a$ = 6.162$\mathring{\mathrm{A}}$, $c$ = 12.291$\mathring{\mathrm{A}}$, obtained both under normal conditions and under the influence of an external electric field with a strength of 500 V $\cdot$ cm$^{-1}$, the structure of the short-range atomic order is established – the number of nearest neighbors – coordination numbers and radius of coordination spheres. It was revealed that in amorphous CuIn$_5$Te$_8$ films obtained under the influence of an external electric field, in which the matrices consist of tetrahedral and octahedral environments of atoms, in opposite to films that are formed outside the field, the number of nearest neighbors remains unchanged, the radius of coordination spheres and interatomic distances are somewhat are shortened.