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

Abstract

Irreproducibility and low conversion efficiency of CdS–Cu2S 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 Cu2−xS 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 Cu2−xS 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.