Photovoltaic performance of thin-film CdS–Cu₂S solar cells with electroformed junctions

Abstract

Irreproducibility and low conversion efficiency of CdS–Cu 2 S solar cells fabricated by the chemiplating process are found to be the result of variations in the surface morphology of the textured CdS surface. To counter such problems, a new technique of barrier formation using direct-current (DC) field-assisted control over the reacting ionic species is described. Photovoltaic data on solar cells fabricated in this way display an overall improvement owing to the prevention of deep-intruded Cu 2−x S growth along the CdS grain boundaries and a closer approximation to stoichiometry. In addition, with the use of the DC potential as a first-order variable these improved characteristics of the junctions have been found to be less sensitive to the Cu 2−x S deposition variables, thus improving general reproducibility. We show data on the cells made by the new technique obtained from spectral response, sheet resistivity, and accelerated life tests.