SOME FABRICATION PROCEDURES FOR ELECTRODEPOSITED CdTe SOLAR CELLS

Abstract

Solar cells with a nCdS/pCdTe heterojunction have been fabricated from elcctrodepositcd CdS and CdTe layers. Sets of cells were made with CdTe films deposited at a range of potentials (QRP) from solutions in which the concentrations of cadmium and of tellurium ions were systematically varied. The properties of the CdTe films and of the cells were examined. The range of values over which suitable solar cells could be made was determined for a given set of processing conditions. The most efficient solar cells were obtained under those processing conditions for solutions with cadmium ion 2.5 M and tellurium ions 120 ppm deposited in a range of QRP's of 20—40 mV (relative to a saturated calomel reference electrode). Morphological studies showed that the most efficient cells had (he largest grain size. Electrical and capacitance measurements showed that the major losses in the solar cell parameters increased with increased polycrystalline structure.