Characterization of zinc–tin–oxide films deposited by radio frequency magnetron sputtering at various substrate temperatures

• Zinc–tin–oxide films were amorphous at below 350 °C.
• With increasing temperature, films transferred from amorphous to crystalline.
• The Hall mobility was in the range of 22.7–23.5 cm2/Vs in the amorphous phases.
• A red-shift in the amorphous state and a blue-shift in the crystalline phases

Zinc–tin–oxide (ZTO) thin films were grown by radio frequency magnetron sputtering on glass substrates at various substrate temperatures. The effects of substrate temperature on the crystalline behavior and electrical and optical properties of the films were studied. The ZTO films were amorphous and maintained their stable amorphous state up to a substrate temperature of 350 °C. With increasing substrate temperature, the ZTO films underwent an amorphous-to-crystalline phase transition. The Hall mobility of the films was in the range of 22.7–23.5 cm2/V s in the amorphous phase and 15.4–19.6 cm2/V s in the crystalline phase. The carrier concentration reached 8.287 × 1019 cm− 3, resulting in a minimum resistivity of 8.75 × 10− 3 Ω·cm in the film deposited at 750 °C. The average transmittance in the visible region was ≥ 85%, and the band gap showed a red-shift in the amorphous phase and a blue-shift in the crystalline phase.