A Review of Low-Temperature Solution-Processed Metal Oxide Thin-Film Transistors for Flexible Electronics

Solution processing, including printing technology, is a promising technique for oxide thin-film transistor (TFTs) fabrication because it tends to be a cost-effective process with high composition controllability and high throughput. However, solution-processed oxide TFTs are limited by low-performance and stability issues, which require high-temperature annealing. This high thermal budget in the fabrication process inhibits oxide TFTs from being applied to flexible electronics. There have been numerous attempts to promote the desired electrical characteristics of solution-processed oxide TFTs at lower fabrication temperatures. Recent techniques for achieving low-temperature (<350 °C) solution-processed and printed oxide TFTs, in terms of the materials, processes, and structural engineering methods currently in use are reviewed. Moreover, the core techniques for both n-type and p-type oxide-based channel layers, gate dielectric layers, and electrode layers in oxide TFTs are addressed. Finally, various multifunctional and emerging applications based on low-temperature solution-processed oxide TFTs are introduced and future outlooks for this highly promising research are suggested.