VOC enhancement of sub-micron CIGS solar cells by sulfization of the Mo surface

In this work, a Mo/MoS2 back contact was investigated for sub-micron-thick Cu(In,Ga)Se2 (CIGS) solar cells. With a H2S reaction, 10 and 30 nm-thick MoS2 films were formed on the Mo back contact prior to CIGS film growth with co-evaporation. The MoS2 layers did not significantly affect the microstructure of CIGS films. However, the MoS2 layer was improved the VOC of CIGS cells by ∼ 50 mV. This is attributed to reduced recombination occurring at the CIGS/Mo interface.