  We reported here a high-performance In2O3/InZnO bilayer metal-oxide (BMO)
thin-film transistor (TFT) using ultra-thin solution-processed ZrOx dielectric.
A thin layer of In2O3 offers a higher carrier concentration, thereby maximizing
the charge accumulation and yielding high carrier mobility. A thick layer of
InZnO controls the charge conductance resulting in low off-state current and
suitable threshold voltage. As a consequence, the BMO TFT showed higher
filed-effect mobility (37.9 cm2/V s) than single-layer InZnO TFT (7.6 cm2/V s).
More importantly, an on/off current ratio of 109, a subthreshold swing voltage
of 120 mV/decade, as well as a threshold voltage shift (less than 0.4 V) under
bias stress for 2.5 hours were obtained simultaneously. These promising
properties are obtained at a low operation voltage of 3 V. This work
demonstrates that the BMO TFT has great potential applications as switching
transistor and low-power devices.
