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.