Study on how the content of selenium in the precursors influences the properties of CuInSe2 thin films

The sputtering with post-selenization technique is a promising process for large-scale manufacturing of Cu(In,Ga)Se2 (CIGS) thin films, where the composition of precursors is important to obtaining CIGS thin films with high quality. We use the CuInSe2 thin film as an example to discuss how the content of selenium in the precursors influences the properties of CuInSe2 thin films. Our results show that the selenium content in the CuInSex precursors strongly influences the grain size, the tomography, phase, elemental distribution and the carrier mobility of the CuInSe2 thin films. Decreasing the selenium content in the precursors can increase the grain size of CuInSe2 and the carrier mobility. On the contrary, increasing the selenium content in the precursors can decrease the roughness of surface and the phase separation.