Enhanced Stability of Solution-Processed Indium-Zinc-Tin-Oxide Transistors by Tantalum Cation Doping

Highly stable metal oxide thin film transistors (TFTs) are required in high-resolution displays and sensors. Here, we adopt a tantalum cation (Ta5+) doping method to improve the stability of zinc-tin-oxide (ZnSnO) TFTs. The results show that Ta5+-doped TaZnSnO TFT with 1 mol% concentration exhibits excellent stability. Compared with the undoped device, the oxygen vacancy defects of TaZnSnO thin films reduce from 38.05% to 18.70%, and the threshold voltage shift (Delta V-th) reduces from 2.36 to 0.71 V under positive bias stress. We attribute the improved stability to the effective suppression of the oxygen vacancy defects, which is confirmed by the XPS results. In addition, we also prepared TaInZnSnO TFT devices with 1 mol% Ta5+ doping concentration. Compared with the 1 mol% Ta5+-doped TaZnSnO TFTs, the mu increases two-fold from 0.12 to 0.24 cm(2)/Vs, and the V-th decreases from 2.29 to 0.76 V in 1 mol% Ta5+-doped TaInZnSnO TFT with an In:Zn:Sn ratio of 4:4:3, while the device remains highly stable with a Delta V-th of only 0.90 V. The injection of Ta5+ provides a novel strategy for the enhancement of the stability in ZnSnO-based TFTs.

Automated summary

High stability of metal oxide thin film transistors (TFTs) is crucial for high-resolution displays and sensors. In this study, tantalum cation (Ta5+) doping is used to enhance the stability of zinc-tin-oxide (ZnSnO) TFTs. The results demonstrate that 1 mol% Ta5+-doped TaZnSnO TFTs exhibit excellent stability, with reduced oxygen vacancy defects and threshold voltage shifts compared to undoped devices. Additionally, Ta5+ doping in TaInZnSnO TFTs leads to improved performance and stability, making it a promising strategy for enhancing the stability of ZnSnO-based TFTs.