High-performance TiO2 thin film transistors using TiO2 as both channel and dielectric

Titanium dioxide (TiO2) have emerged as a versatile multifunctional material, which enables numerous device applications such as optical sensor, solar cell, thin film transistors (TFTs), and memristive device [1]. To successfully apply TiO2 in these devices, the electrical properties of TiO2 films need to be well studied. Previously, we demonstrated the conductivity transition of the nearly stoichiometric TiO2 films via the crystallinity engineering. High-performance TFTs with polycrystalline TiO2 (poLY-TiO2) as the active channel and InAIN/GaN MISHEMTs with amorphou $\text{TiO}_{2}(\mathrm{a}-\text{TiO}_{2})$ as the gate dielectrics were demonstrated [2]. Herein, we report for the first time a proof-of-concept TiO2 TFT using poly- TiO2 channel and $\mathrm{a}-\text{TiO}_{2}$ dielectric. These TiO2 TFTs show a high device performance including a high on/off current ratio $(\mathrm{I}_{\text{on}}/\mathrm{I}_{\text{off}})$ of 4×10⁸ and a low subthreshold swing (SS) of 120 m V/dec under a battery-compatible voltage $(< 2\mathrm{V})$, suggesting their strong potential for portable electronics.