High mobility and low operating voltage ZnGaO and ZnGaLiO transistors with spin-coated Al₂O₃ as gate dielectric

Spin-coated alumina serving as a gate dielectric in thin film transistors shows interesting dielectric properties for low-voltage applications, despite a moderate capacitance. With Ga singly doped and Ga, Li co-doped ZnO as the active channel layers, typical mobilities of 4.7 cm² V⁻¹ s⁻¹ and 2.1 cm² V⁻¹ s⁻¹ are achieved, respectively. At a given gate bias, the operation current is much smaller than the previously reported values in low-voltage thin film transistors, primarily relying on the giant-capacitive dielectric. The reported devices combine advantages of high mobility, low power consumption, low cost and ease of fabrication. In addition to the transparent nature of both the dielectric and semiconducting active channels, the superior electrical properties of the devices may provide a new avenue for future transparent electronics.