Towards environmental friendly solution-based ZTO/AlO_x TFTs

Solution based deposition has been recently considered as a viable option for low-cost flexible electronics. In this context research efforts have been increasingly centred on the development of suitable solution-processed materials for oxide based transistors. Nevertheless, the majority of synthetic routes reported require the use of toxic organic solvents. In this work we report on a new environmental friendly solution combustion synthesis route, using ethanol as solvent, for the preparation of indium/gallium free amorphous zinc-tin oxide (ZTO) thin film transistors (TFTs) including AlO_x gate dielectric. The decomposition of ZTO and AlO_x precursor solutions, electrical characterization and stability of solution processed ZTO/AlO_x TFTs under gate-bias stress, in both air and vacuum atmosphere, were investigated. The devices demonstrated low hysteresis (ΔV = 0.23 V), close to zero turn on voltage, low threshold voltage (V_T = 0.36 V) and a saturation mobility of 0.8 cm² V⁻¹ s⁻¹ at low operation voltages. Ethanol based ZTO/AlO_x TFTs are a promising alternative for applications in disposable, low cost and environmental friendly electronics. (invited article)