Growth of Zn doped Cu(In,Ga)Se_2 thin films by RF sputtering for solar cell applications

摘要

Cu(In, Ga)Se_2 (CIGS) surface was modified with Zn doping using a magnetron sputtering method. CulnGa:Zn precursor films targeting a CuIn_(0.7)Ga_(0.3)Se_2 stoichiometry with increasing Zn content from 0 to 0.8 at% were prepared onto Mo-coated glass substrates via co-sputtering of Cu-Ga alloy, In and Zn targets. The CulnGa:Zn precursors were then selenized with solid Se pellets. The structures and morphologies of grown Zn doped CIGS films were found to depend on the Zn content. At zinc doping level ranging between 0.2 and 0.6 at%, the Zn doping improved the crystallinity and surface morphology of CIGS films. Compared with the performance of the non-doped CIGS cell, the fabricated CIGS solar cell displayed a relative efficiency enhancement of 9-22% and the maximum enhancement was obtained at a Zn content of 0.4 at%.