CONTROL OF THE ELECTRODEPOSITION OF CADMIUM TELLURIDE - EFFECT OF THEQUASI-REST POTENTIAL

The standard method for the control of the electrodeposition of CdTe t hin films for photovoltaic applications is by monitoring the quasi-res t potential (QRP). The importance of the QRP has been tested by deposi ting CdTe onto tin-doped indium oxide (ITO)/CdS substrates over a rang e of QRPs from -0.20 to -0.65 V vs. Ag/AgCl, covering the observed pot ential range over which CdTe deposition occurs. The effect of the QRP on the performance of the CdS/CdTe solar cells was assessed in terms o f the structural and morphological properties of the CdTe films, in ad dition 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 C dTe occurred at a relatively constant applied potential, confirming ex perimentally for the first time the influence of the predicted potenti al of perfect stoichiometry in compound semiconductor electrodepositio n.