Ultrathin CdTe Solar Cells with MoO 3− x /Au Back Contacts

We report on the fabrication and characterization of CdTe thin-film solar cells with Cu-free MoO 3− x /Au back contacts. CdTe solar cells with sputtered CdTe absorbers of thicknesses from 0.5 to 1.75 μ m were fabricated on Pilkington SnO 2 :F/SnO 2 -coated soda–lime glasses coated with a 60- to 80-nm sputtered CdS layer. The MoO 3− x /Au back contact layers were deposited by thermal evaporation. The incorporation of MoO 3− x layer was found to improve the open circuit voltage ( V OC ) but reduce the fill factor of the ultrathin CdTe cells. The V OC was found to increase as the CdTe thickness increased.