title: Improved electrical performance and bias stability of solution-processed active bilayer structure of indium zinc oxide based TFT.
abstract: We fabricated active single- and bilayer structure thin film transistors (TFTs) with aluminum or gallium doped (IZO:Al or IZO:Ga) and undoped indium zinc oxide (IZO) thin film layers using an aqueous solution process. The electrical performance and bias stability of these active single- and bilayer structure TFTs were investigated and compared to reveal the effects of Al/Gal doping and bilayer structure. The single-layer structure IZO TFT shows a high mobility of 19 cm(2)/V · s with a poor positive bias stability (PBS) of ΔVT + 3.4 V. However, Al/Ga doped in IZO TFT reduced mobility to 8.5-9.9 cm(2)/V · s but improved PBS to ΔVT + 1.6-1.7 V due to the reduction of oxygen vacancy. Thus, it is found the bilayer structure TFTs with a combination of bottom- and top-layer compositions modify both the mobility and bias stability of the TFTs to be optimized. The bilayer structure TFT with an IZO:X bottom layer possess high mobility and an IZO bottom layer improves the PBS.
authors.affiliation: Laboratory of Optical Materials and Coating (LOMC), Deptartment of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Republic of Korea.
authors.forename: Jin-Suk
authors.initials: JS
authors.lastname: Seo
authors.forename: Byeong-Soo
authors.initials: BS
authors.lastname: Bae
keywords: active bilayer structure; bias stability; field effect mobility; indium zinc oxide; metal oxide TFT; solution process