O₂ and H₂O Barrier-Based High Reliability and Stability Using Polytetrafluoroethylene Passivation Layer for Solution Processed Indium Oxide Thin Film Transistors

Abstract

The excellent chemical stability and hydrophobicity of Polytetrafluoroethylene (PTFE) polymer lead to its applicability in high-performance flexible electronic appliances. Though the detailed investigation for PTFE passivated metal oxide thin-film transistors (TFTs) is still lacking. Here, we report the highly stable oxygen barrier based on the PTFE passivation layer (PVL) spin-coated upon the lowtemperature solution-processed indium oxide (In2O3) TFTs. Particularly, by using the solution-process method, fabrication cost and multiple time-consuming steps are eliminated in the counterpart of the radio frequency magnetron sputtering. The PTFE PVL can significantly suppress the adsorption of surrounding moisture and oxygen from environments owing to its most chemically robust carbon-fluorine bond. In addition, the comprehensive electrical performance in terms of the saturation mobility, on-off current ratio, threshold voltage, subthreshold swing, and interface trap density of the In2O3 TFTs passivated with different weight ratios of PTFE are compared. The results show that 1 wt.% PTFE passivated In2O3 TFT demonstrates a drastically reduced threshold voltage and highest stability under constant bias. Consequently, oxygen barrier-based PTFE is a promising PVL material for various emerging electronic devices.

Keywords

• Solution-process
• indium oxide thin film transistor
• polytetrafluoroethylene
• passivation layer
• stability
• spin-coating