Transparent flexible fluorine-doped indium zinc oxide (IZO:F) thin-film transistors (TFTs) were demonstrated using the spin-coating method of the metal fluoride precursor aqueous solution with annealing at 200°C for 2 hrs on polyethylene naphthalate films. The proposed thermal evolution mechanism of metal fluoride aqueous precursor solution examined by thermogravimetric analysis and Raman spectroscopy can easily explain oxide formation. The chemical composition analysed by XPS confirms that the fluorine was doped in the thin films annealed below 250°C. In the IZO:F thin films, a doped fluorine atom substitutes for an oxygen atom generating a free electron or occupies an oxygen vacancy site eliminating an electron trap site. These dual roles of the doped fluorine can enhance the mobility and improve the gate bias stability of the TFTs. Therefore, the transparent flexible IZO:F TFT shows a high mobility of up to 4.1 cm2/V·s and stable characteristics under the various gate bias and temperature stresses.

Metal-oxide semiconductors have attracted considerable attention as next-generation circuitry for displays and energy devices because of their unique transparency and high performance. We propose a simple, novel and inexpensive 'aqueous route' for the fabrication of oxide thin-film transistors (TFTs) at low annealing temperatures (that is, o200 1C). These results provide substantial progress toward solution-processed metal-oxide TFTs through naturally formed, unique indium complex and post annealing. The fabricated TFTs exhibited acceptable electrical performance with good large-area uniformity at low temperatures. Additional vacuum annealing facilitated the condensation reaction by effectively removing byproduct water molecules and resulted in the activation of the In 2 O 3 TFT at low annealing temperatures, even temperatures as low as 100 1C. In addition, we have demonstrated that the flexible and transparent oxide TFTs on plastic substrates exhibit good resistance to external gate bias stress. INTRODUCTIONMetal-oxide semiconductors (MOSs) are a unique class of materials that have both transparency and electronic conductivity. 1-3 Increasing demand for transparent semiconducting active materials has resulted in increased attention on the MOSs for next-generation electronics, including electronics for use in high-performance, flexible and transparent applications, because of their favorable field-effect mobility, high optical transparency and good environmental stability. 4,5 In the early studies, these materials were primarily prepared using a vacuum process. 6,7 Although the vacuum-based deposition method has advantages, the high fabrication cost and large-area device uniformity restrict its areas of application. We suggest a simple and novel 'aqueous route' for the fabrication of oxide thin-film transistors (TFTs) at low annealing temperatures (that is, o200 1C). These results provide substantial progress toward solutionprocessed metal-oxide TFTs via a unique indium complex (IC) and post annealing. In addition, we have demonstrated that the flexible and transparent oxide TFTs on plastic substrates exhibit good resistance to external gate bias stress.The solution-based synthesis approach is considered a promising solution to the issues of fabrication cost and device uniformity. This

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.

Metal oxide semiconductor attracts considerable attentions for driving circuit of next generation displays and energy devices owing to their simultaneous transparency and high electrical performance. We report fluorine doped zinc tin oxide (ZTO:F) and indium zinc oxide (IZO) thin-film transistors (TFT) via aqueous route. The aqueous route enables the fabrication of oxide TFT at low temperature with reasonable cost. The ZTO:F TFT exhibits good electrical performance and stability over electrical stress due to the effective removal of oxygen vacancy and generation of carrier by F doping. The IZO TFTs also shows good performance in terms of mobility and operation accuracy. Finally, the optimized IZO TFT is fabricated on plastic substrate with 250 ℃ annealing and the device exhibits sufficient performance for operation of various displays and basic circuitries.