Exciton absorption spectrum of thin films of ternary compounds in the CsCl-CuCl system

Abstract

The absorption spectra of thin films (CsCl)1-x(CuCl)x were studied at T=90K in the spectral range 2 – 6 eV. From the analysis of the spectra, the formation of CsCu2Cl3 and Cs2CuCl3 compounds in the CsCl – CuCl system was established. The Cs2CuCl3 compound is stable only in a vacuum; in air, it apparently decomposes into CsCu2Cl3 with a disordered crystal lattice and CsCl. The exciton spectrum of both compounds is interpreted on the basis of transitions in the Cu+ ion. A one-dimensional (1D) character of excitons in CsCu2Cl3 and a two-dimensional (2D) character in Cs2CuCl3 was established