High-Performance Solution-Processed ZnSnO TFTs with Tunable Threshold Voltages

In this work, we had investigated the solution-processed zinc-tin oxide (ZTO) semiconductors using metal chloride precursors and the sol-gel method. We studied the effects of different processing conditions, such as different procedures of spin-coating and annealing, on thin-film transistor (TFT) characteristics (e.g., mobility, threshold voltages etc.). High-performance In-free solution-processed ZTO TFTs with mobilities up to 10–17 cm2/V⋅s and threshold voltages being tunable from positive to negative (i.e. from enhancement mode to depletion mode) had been achieved. The capability to control operation modes of TFTs provides the freedom to implement higher-performance TFT circuits (e.g. high-gain inverters demonstrated) using only solution-processed n-type ZTO TFTs. Using these two types of ZTO TFTs, depletion-load inverters were implemented, demonstrating enhanced characteristics in inverter characteristics compared to the enhancement-load inverters.