MgCl2 activation of CdS films: An alternative for CdCl2

A detailed study on MgCl2 solution treatment on chemical bath deposited CdS (CBD-CdS) is reported. MgCl2 treated samples have shown the higher VOC and ISC values in the photoelectrochemical (PEC) cell compared to non-treated samples. The improved PEC cell performance in the MgCl2 treated samples were found to be higher carrier concentration and improved effective surface area as well as grain boundary passivation. The MgCl2 treatment was found to increase the cluster size of CdS thin films and the formation of clusters was identified to be due to coalescence of small clusters. Increasing the duration of MgCl2 treatment led to formation of large and densely packed surface morphology. Additionally, the relative flat band potential (VFB) value was found to be tunable with MgCl2 treatment duration and the best photo-activity and highest density of packing was observed for the CdS films which underwent MgCl2 treatment for 14 min.