Eco-Friendly, Water-Induced In2O3 Thin Films for High-Performance Thin-Film Transistors and Inverters

Solution-driven metal–oxide semiconductors have recently received much attention as a viable option for low-cost, flexible electronic devices. In this paper, a simple, environmentally friendly aqueous solution method has been adopted to deposit an ultrathin In
₂
O
₃
semiconductor layer with a thickness of about 7 nm at low temperature. Then, in combination with the advantages of atomic layer deposition (ALD) technology, an ultrathin aluminum oxide dielectric layer of about 20 nm was prepared to fabricate high-performance In
₂
O
₃
/Al
₂
O
₃
thin-film transistor (TFT) devices. The device with optimized annealing temperature of 280 °C has demonstrated an excellent electrical performance, including a high saturation mobility of 11.85 cm
²
· V
⁻¹
· s
⁻¹
, a large ON/OFF current ratio of 10
⁶
, a low threshold voltage of 0.12 V, a small hysteresis voltage of 0.05 V, and a small density of interface state of
$\textsf {1.97} \times \textsf {10}^{\textsf {12}}$
cm
⁻²
, respectively. To demonstrate the potential of In
₂
O
₃
/AlO
_x
TFT toward more complex logic applications, the unipolar inverter was further constructed and exhibited a high gain of 5. Importantly, all these device parameters were obtained at an ultralow operating voltage of 2.5 V. As a result, it can be inferred that the water-induced In
₂
O
₃
TFTs based on ALD-derived Al
₂
O
₃
dielectrics have a potential application as a promising alternative for low-cost, low-power consumption, and large-area environmentally friendly oxide flexible electronics.