Water as Origin of Hysteresis in Zinc Tin Oxide Thin-Film Transistors

The hysteresis behavior of transparent zinc tin oxide (ZTO) thin film transistors (TFTs) is identified to be a result of short-term bias stress induced by the measurement. The related density of shallow defect states can be adjusted by the amount of water in the ambient. Time-resolved studies of the TFTs under varied ambient demonstrate that hysteresis can be immediately switched on and off by the adsorption and desorption of water, respectively. These findings are expected to be of general importance also for other oxide-based TFTs.