Organic Thin Film Transistors

 Recently, organic thin-film transistors (OTFTs) have attracted particular attention as a suitable candidate to be applied to flexible and wearable electronics, such as sensors, memories, light-emitting diodes, and switching devices for active-matrix flat-panel displays because they exhibit several advantages including good flexibility, low processing temperature, and potential usage in inkjet printing.

 In our lab, we propose a water-debonding process for fabricating flexible TFTs that separates the carrier substrate and device while minimizing damages to the device using water-soluble PVA as a release layer. Further, it was fabricated to be fully protected by solution-processed CYTOP encapsulation for the waterproof property with moisture resistance. Consequently, we managed to implement ultrathin flexible TFTs with CYTOP encapsulation by debonding process.

Oxide Thin Film Transistors

 Among the oxide TFTs, amorphous indium-gallium-zinc-oxide (a-IGZO) TFTs using a mixture of In-Ga-Zn-O are particularly attractive due to their excellent electrical characteristics, including a high on/off ratio, good uniformity, low processing temperature, and high adapt ability to various fabrication processes.

 In our lab, we fabricate a-IGZO TFTs with the IGZO layer deposited by solution process as the active layer. Further we fabricated IGZO TFTs with solution-processed CYTOP passivation to improve the stability of a-IGZO TFTs. This improvement was caused by a reduction of Vo and a widened band gap of a-IGZO through the F diffusion effect. In addition, the CYTOP passivation layer maintained excellent properties as a barrier against moisture. Consequently, we managed to improve electrical characteristics of IGZO TFTs with CYTOP.