ZnS thin films for visible-light active photoelectrodes: Effect of film morphology and crystal structure

The photoelectrochemical (PEC) performance of zinc sulfide (ZnS) thin films under visible light has been studied as a function of the fabrication conditions. In particular, N₂ background gas during film deposition was exploited to tune the film crystal structure and surface roughness. The photocurrent was highest for films with relatively large crystallite size in the wurtzite structure and high surface roughness. Films with such optimized characteristics showed a maximum photocurrent density of 1.6 mA/cm² under visible-light irradiation. Hence, this work provides a guide for how ZnS thin films with high PEC performance, particularly under visible light, can be realized.