Two-stage processed high-quality famatinite thin films for photovoltaics

Famatinite (Cu3SbS4) thin films were prepared by annealing chemically grown Sb2S3-CuS stacks in a graphite box at 370-430 degrees C for 30 min under sulfur and N-2 atmospheres. The films grown at 370 degrees C contain a minor CuSbS2 phase with dominant Cu3SbS4. Those films prepared at 400 degrees C and 430 degrees C are single-phase Cu3SbS4 with a tetragonal structure and lattice parameters a = 0.537 nm and b = 1.087 nm and a crystallite size of 25 nm. The grain size of the films increases as the annealing temperature is increased to 400 degrees C and subsequently decreases. The film morphology is compact and void-free with a grain size of 300-800 nm at 400 degrees C. The band gap of the films is 0.89 eV. The films exhibited p-type electrical conductivity and a relatively high hole mobility of 14.70 cm(2)V(-1)s(-1) at 400 degrees C. Their attractive optoelectronic properties suggest that these films are suitable as solar cell absorber layers. (C) 2017 Elsevier Ltd. All rights reserved.