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 V_OC of CIGS cells by ~ 50 mV. This is attributed to reduced recombination occurring at the CIGS/Mo interface.