Deposition and characterization of (Cd sub(x) Zn sub(1-x)) S thin films

Thin films of (Cd sub(x) Zn sub(1-x)) S were deposited on the substrates of soda-lime glass and borosilicate glass by coevaporation of CdS and ZnS, using the technique of hot wall. The temperatures for substrate (2000C), wall (3500C), CdS source (9000-10000C) and ZnS source (9000-12000C) were found to be optimum for formation of the films with deposition rates in the range of 0.5 μm.min-1. The films obtained were with Wurtzite structure, with the crystallographic planes oriented in (001) direction. A linear variation of the parameter C0 of hexagonal lattice with the concentration of Zn, in the range of 20% to 60%, was observed. For lower and higher concentration outside this range there was a tendency of saturation of C0. Measurements of Hall voltage and resistivity demonstrated the mobility and carrier concentration in the range of 10-40 cm2v-1sec-1 and 1.45 x 1019 - 3.83 x 1020 cm-3, respectively, whereas the resistivity of the films ranged from 2.11 x 10-2 Ω.cm for the Zn concentration variation from 20% to 70%. Measurements of optical absorption revealed linear variation of refractive index of the films with Zn concentration for the wavelenght in the range of 0.5 to 2.0 μm. (Cd sub(x) Zn sub(1-x)) S films with 0.7 < x < 0.8 should given a better lattice watching for the heterojunction of (Cd sub(x) Zn sub(1-x)) S-Cu2S. (Author)