The author is affiliated with Thin Film Electronics Group, MANA, NIMS and conducts research on thin-film transistors.

Tellurium oxide is expected to be used as a p-type semiconductor material. We investigated TeOx thin films fabricated by vacuum deposition using a mixture of TeO₂ powder and W powder in Al₂O₃ crucibles and evaluated its thin-film transistor (TFT) characteristics. P-Type TeO_x thin films were obtained when W was added at a weight ratio of 15% or more relative to TeO₂. However, the films became insulators and exhibited no electrical conductivity when the ratio was 10% or less. X-ray photoelectron spectroscopy analysis (XPS) revealed that the TeO_x thin films contained approximately 5% or more Te–Te bonds (Fig. 1). Because W–O bonds exhibit a higher dissociation energy than Te–O bonds, TeO₂ was considered to be reduced by W. In addition, W was not present in the film and was used solely for the reduction of TeO₂. The results manifest that when TeO_x TFTs are fabricated by vacuum deposition, the addition of an appropriate amount of reducing agent to the raw material is essential to form an adequate amount of Te–Te bond

1. S. Kato et al., Appl. Phys. Lett. 128, 212109 (2026). DOI: 10.1063/5.0329188