Molybdenum oxide contacts for nanowire CdS-CdTe solar cells

Using a 10nm thick molybdenum oxide (MoO_3-x) layer as a transparent and low barrier contact to p-CdTe, we demonstrate nanowire CdS-CdTe solar cells with a power conversion efficiency of 11% under front side illumination. Annealing the as-deposited MoO₃ film in N₂ resulted in a reduction of the cell´s series resistance from 10 Ω/cm² to 7.7 Ω/cm², and efficiency improvement from 9.9% to 11%. Under illumination from the back, the MoO_3-x/Au side, the nanowire solar cells yielded J_sc of 20.9mA/cm² and efficiency of 8.7%. This work has implications toward enabling a novel superstrate structure nanowire CdS-CdTe solar cell on Al foil substrate by a low cost roll-to roll fabrication process.