The effect of current density on the composition, structure, morphology and optical properties of galvanostatically electrodeposited nanostructured cadmium telluride films

摘要

Cadmium telluride (CdTe) films were electrodeposited galvanostatically on fluorine doped tin oxide (FTO) substrates at various applied current densities. The electrodeposited films were characterized using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and optical absorption spectroscopy techniques. The results showed that amount of cadmium in the deposited films were enhanced by increasing the applied current density. It was observed that an applied current density of 18 mA/cm(2) produced Cd:Te films with 1:1 stoichiometry. Moreover, the maximum optical absorption and the closest band gap value to the expected one for CdTe (1.45 ev) were observed in the case of stoichiometric films which had less porosity and larger crystallite size among the films that were electrodeposited at applied current densities other than the optimum value. In addition, those films that were heat treated had less porosity in their structure, larger crystallite size and less band gap energy compared to the films without heat treatment.