Antimony-induced grain growth and properties modification of Cu(In, Al)Se2 thin films fabricated by selenization of sputtered stacked precursors

• The Sb-doping content dependence of the properties of CIAS films has been studied.
• The phase-pure Sb-doped CIAS films with a decreased defects can be obtained.
• Significant Sb-induced grain size increase and smooth surface has been observed.
• The Sb-doped device demonstrates two-orders of magnitude in current amplification.

The influence of antimony (Sb) doping content on the structural properties of Cu(In, Al)Se2 (CIAS) thin films and performance of photodetector has been investigated systematically. Here, we report the high-quality, phase-pure and well-crystallized CIAS thin films containing Sb element, where the lattice defects can be restrained effectively. Moreover, significant Sb-induced grain size enhancement, dense and smooth surface morphology can be observed, which originates from that the low melting point Sb-based compounds play as fluxing agents during the grain growth process. Most importantly, after Sb doping, the photodetector with the Al:ZnO (AZO)/CIAS/Mo structure demonstrates a two-orders of magnitude in photocurrent amplification, which indicates the reduced recombination of charge carriers in the depletion region. These findings provide additional insight into their use for the forthcoming photodetector application.