Manipulation of MoSe₂ films on CuIn(Ga)Se₂ solar cells during rapid thermal process

In this study, the CuIn(Ga)Se₂ (CIGS) crystalline quality and MoSe₂ thickness of films produced by the rapid thermal selenization process under various selenization pressures were investigated. When the selenization pressure increased from 48 Pa to 1.45 × 10⁴ Pa, the CIGS films were smooth and uniform with large crystals of varying sizes. However, the MoSe₂ thicknesses increased from 50 nm to 2,109 nm, which created increased contact resistivity for the CIGS/MoSe₂/Mo structures. The efficiency of CIGS solar cells could be increased from 1.43% to 4.62% due to improvement in the CIGS crystalline quality with increasing selenization pressure from 48 Pa to 1.02 × 10³ Pa. In addition, the CIGS crystalline quality and MoSe₂ thickness were modified by the pressure released valve (PRV) selenization process method. The crystalline qualities of the CIGS films were similarly affected by the selenization pressure at 1.02 × 10³ Pa in the PRV selenization method and the MoSe₂ thicknesses were reduced from 1,219 nm to 703 nm. A higher efficiency of 5.2% was achieved with the thinner MoSe₂ obtained by using the PRV selenization method.