Control of the electrodeposition of cadmium telluride: effect of the quasi-rest potential

Abstract

The standard method for the control of the electrodeposition of CdTe thin films for photovoltaic applications is by monitoring the quasi-rest potential (QRP). The importance of the QRP has been tested by depositing CdTe onto tindoped indium oxide (ITO)/CdS substrates over a range of QRPs from –0.20 to –0.65 V vs. Ag/AgCl, covering the observed potential range over which CdTe deposition occurs. The effect of the QRP on the performance of the CdS/CdTe solar cells was assessed in terms of the structural and morphological properties of the CdTe films, in addition to the photovoltaic properties of the final devices. The value of the QRP during deposition appeared to exert no influence on any of the measured parameters. In contrast, the deposition of high-quality CdTe occurred at a relatively constant applied potential, confirming experimentally for the first time the influence of the predicted potential of perfect stoichiometry in compound semiconductor electrodeposition.