The effects of CTAB concentration on the properties of electrodeposited cadmium telluride films

Abstract

The effects of cetyltrimethylammonium bromide (CTAB) concentrations on the properties of electrochemically deposited cadmium telluride films have been investigated using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and photoelectrochemical measurements. The results show that CTAB concentration plays a very important role in directing the morphology evolution of thick films from cabbage-shaped CdTe arrays to high density nanoneedle structures. Various CdTe structures can be obtained by changing the CTAB concentration in the electrolyte. Meanwhile, it was observed that the Te/Cd ratio of the as-deposited thin film decreased with the increase of CTAB concentration. When CTAB concentrations are 0.02 M, the composition of CdTe film is near stoichiometric and Te is in excess. Growth mechanisms for shape-selective CdTe synthesis are proposed based on these results. In addition, we found that the device based on the aligned cabbage-shaped CdTe array-on-Ni configuration prepared at 0.02 M CTAB demonstrates excellent photoelectrical properties, which is ascribed to the large absorption coefficient of the material and also suggests a good electronic structure quality of the cabbage-shaped rods.