Growth of Ag(In,Ga)Se2 Films by Modified Three-Stage Method and Influence of Annealing on Performance of Solar Cells

A modified three-stage method was introduced to deposit high-efficiency Ag(In,Ga)Se-2 (AIGS) solar cells. Cu(In,Ga)Se-2 (CIGS) and AIGS films were deposited by conventional and modified three-stage methods, respectively, to enable a comparison of the diffusion processes of Ag and Cu into (In,Ga)(2)Se-3 films during the second stage. The diffusion coefficient of Ag is less than that of Cu, causing the easy segregation of Ag in the film. High-temperature annealing could improve the diffusion coefficient of Ag, consequently improving the solar cell performance. Air annealing of the AIGS solar cell can also improve the cell performance significantly, and finally an efficiency of 9.2% was achieved. (C) 2012 The Japan Society of Applied Physics