Effect of thickness on the properties of Cu(Inx,Ga1-x)Se2 back conduct Mo thin films prepared by DC sputtering

Abstract

In this study, Mo thin films which used in Cu(Inx Ga1-x)Se2 (CIGS) thin film solar cells as back conduct were deposited on soda-lime glass substrates via DC magnetron sputtering under certain conditions. A series of Mo thin films prepared of various thicknesses was obtained in different sputtering deposition times. The microstructure, electrical resistivity and mechanical strain property of Mo thin films, which may be varied by controlling the thickness, were investigated by XRD, SEM, four probes technology and Scotch tape test. As the results showed, the thicknesses of the films increased linearly with the sputtering time. With increasing thickness, the films' crystal growth showed a change from (110) preferred orientation to (211) preferred orientation. The sheet resistance sharply reduced to 2 Ω/⇑ with the increase of (110) peak height and the resistivity linearly decreased to 0.96×10-4 Ω·cm due to the level of (110) preferred orientation. The films surface has porous (fish-like) grain morphology and intergranular voids. All the films are in a tensile state, and the inner strain decreased with the increase of the thickness.