Post-annealing treatment of a-GeSe thin films for photovoltaic application

p-GeSe is a promising absorber material for thin-film solar cell. In this letter, p-GeSe thin films were fabricated by post-annealing treatment of a-GeSe films. We systematically studied the effects of annealing time on the crystallinity, surface morphology and photoelectric properties of GeSe films, and we found the bandgaps, optical constant and conductivity of GeSe films have shown significant variations when GeSe films transformed from amorphous to polycrystalline. The bandgap of GeSe film can be tuned in a range of 1.17-1.42 eV and the hole mobility can reach as high as 15.02 cm(2) V(-1)s(-1). Finally, a thin-film solar cell based on FTO/CdS/p-GeSe/Au configuration was fabricated and has realized an efficiency of 0.65% and a short circuit current of 12.61 mA/cm(2).