Ultrathin CdTe Solar Cells with MoO3−x/Au Back Contacts

We report on the fabrication and characterization of CdTe thin-film solar cells with Cu-free MoO3−x/Au back contacts. CdTe solar cells with sputtered CdTe absorbers of thicknesses from 0.5 to 1.75 μm were fabricated on Pilkington SnO2:F/SnO2-coated soda–lime glasses coated with a 60- to 80-nm sputtered CdS layer. The MoO3−x/Au back contact layers were deposited by thermal evaporation. The incorporation of MoO3−x layer was found to improve the open circuit voltage (VOC) but reduce the fill factor of the ultrathin CdTe cells. The VOC was found to increase as the CdTe thickness increased.