The effect of the transparent conductive oxide on the performance of thin film CdS/CdTe solar cells

Thin film CdS/CdTe solar cells fabricated on SnOx-coated glass have been fo und to give higher efficiencies than similar cells produced on indium-tin o xide (ITO) coated glass substrates. Further investigation implicated the Cd S/ITO interface as the cause of the problem; current-voltage measurements r evealed that on heating in air the CdS/ITO junction became rectifying. This is consistent with recently reported findings which show that the work fun ction of ITO is raised above that of CdS by oxidative treatments (such as h eating in air) which would make the ITO/CdS junction rectifying rather than ohmic.