Low voltage-driven, high-performance TiO₂ thin film transistors with MHz switching speed

High-speed circuits based on thin film transistors (TFTs) show promising potential applications in biomedical imaging and human-machine interactions. One of the critical requirements for high-speed electronic devices lies in high-frequency switching or amplification at low voltages, typically driven by batteries (∼3.0 V). To date, however, most electrical performances of metal oxide TFTs are measured under direct current (DC) conditions, and their dynamic switching behaviour is scarcely explored and studied systematically. Here in this work, we present low voltage-driven, high-performance TiO₂ thin film transistors, which can be operated at a switching speed of MHz. Our proposed TiO₂ TFTs demonstrated a high on-off ratio of 10⁷, together with a subthreshold swing (SS) of ∼150 mV Dec^-1 averaged over four orders of magnitude, which can be further reduced below 100 mV Dec^-1 when the temperature cools to 77 K. Additionally, the TiO₂ TFTs exhibit excellent gate-pulse switching at various frequencies ranging from 1.0 Hz to 1.0 MHz. We also explored the potential application of the TiO₂ TFTs as logic gates by constructing a resistive-loaded inverter, which shows stable operation at 10 kHz frequency and various temperatures. Thus, our results show the great potential of TiO₂ TFTs as a new platform for high-speed electronic applications.