Transparent and conducting Zn-Sn-O thin films prepared by combinatorial approach

Abstract Zn-Sn-O (ZTO) films with continuous compositional gradient of Sn 16–89 at.% were prepared by co-sputtering of two targets of ZnO and SnO 2 in a combinatorial method. The resistivities of the ZTO films were severely dependent on oxygen content in sputtering gas and Zn/Sn ratio. Except for the films with Sn 16 at.%, all the as-prepared films were amorphous and maintaining the stable amorphous states up to the annealing temperature of 450 °C. Annealing at 650 °C resulted in crystallization for all the composition, in which ZnO, Zn 2 SnO 4 , ZnSnO 3 , and SnO 2 peaks were appeared successively with increasing Sn content. Above Sn 54 at.%, the ZTO films were deduced to have a local structure mixed with ZnSnO 3 and SnO 2 phases which were more conductive and stable in thermal oxidation than ZnO and Zn 2 SnO 4 phases. The lowest resistivity of 1.9 × 10 −3  Ω cm was obtained for the films with Sn 89 at.% when annealed at 450 °C in a vacuum. The carrier concentrations of the amorphous ZTO films that contained Sn contents higher than 36 at.% and annealed at 450 °C in a vacuum were proportional to the Sn contents, while the Hall mobilities were insensitive to Sn contents and leveling in the range of 23–26 cm 2 /V s.