Rapid thermal processing of Cu2ZnSnSe4 thin films

Optimized conditions for conventional thermal processing of Cu₂ZnSnSe₄ are not readily transferable to the rapid thermal processing, though it is of high importance to test the industrial viability of this material. Here the effect of layer order has been investigated for Cu-Zn(O)-Sn precursor stacks selenized by rapid thermal processing to form Cu₂ZnSnSe₄ thin films. The ordering is shown to have significant effects on the film properties, including composition and elemental loss, morphology, and secondary phase formation. Optoelectronic properties of devices based on these films also show a dependence on precursor stack order. The best performing device has a conversion efficiency of 4.3%, and uses a stack order of Sn/Zn/Cu.