The preferential growth of pyrite films prepared by thermal sulfuration of Fe2O3 films

Pyrite thin films were prepared by the sol-gel dip coating process and sulfuration treatment. The evolution of crystal orientation for the pyrite films was investigated as a function of sulfuration temperature. And the effect of crystal orientation on the electrical and optical properties was studied. It was found that films show (1 1 1) preferred orientation after sulfurized at low temperature. However, the (2 0 0) and (3 1 1) mixed preferred orientations were observed when pyrite films were sulfurized at higher temperature. Experimental results also indicate that the carrier concentration is high when the films show (1 1 1) preferred orientation. And the optical absorption coefficient is also large when the films grow with (1 1 1) preferred orientation. It is speculated that surface free energy could play a more important role in determination of preferred orientation when films were sulfurized at low temperature. However, the strain energy plays a more important role in determination of preferred orientation when films were sulfurized at higher temperature. (C) 2011 Elsevier B.V. All rights reserved.