Improved device performance of solution-processed zinc-tin-oxide thin film transistor effects using graphene/Al electrode

We report on improved device performances of solution-processed zinc tin oxide (ZTO) thin film transistors (TFTs) using a graphene interlayer between an Al electrode and ZTO. The ZTO TFTs with a high-temperature annealing process at 600 degrees C show improved output characteristics compared to ones with annealing at relatively lower temperatures, which can be attributed to the reduced impurity and condensed surface state. The ZTO TFTs using the Ohmic contact of the graphene/Al electrode (G-ZTO TFTs) with an optimized annealing process exhibited a good saturation mobility of (6.96 cm(2)V.s)(-1), a subthreshold slope of 1.52 V dec(-1) and a threshold voltage shift toward a negative bias direction. The improvement of device performances of G-ZTO TFTs can be contributed to good Ohmic contact formation by using graphene inserted between the ZTO active layer and the Al electrode.