Combustion-assisted low-temperature ZrO₂/SnO₂ films for high-performance flexible thin film transistors

We developed high-performance flexible oxide thin-film transistors (TFTs) using SnO₂ semiconductor and high-k ZrO₂ dielectric, both formed through combustion-assisted sol-gel processes. This method involves the exothermic reaction of fuels and oxidizers to produce high-quality oxide films without extensive external heating. The combustion ZrO₂ films were revealed to have an amorphous structure with a higher proportion of oxygen corresponding to the oxide network, which contributes to the low leakage current and frequency-independent dielectric properties. The ZrO₂/SnO₂ TFTs fabricated on flexible substrates using combustion synthesis exhibited excellent electrical characteristics, including a field-effect mobility of 26.16 cm²/Vs, a subthreshold swing of 0.125 V/dec, and an on/off current ratio of 1.13 × 10⁶ at a low operating voltage of 3 V. Furthermore, we demonstrated flexible ZrO₂/SnO₂ TFTs with robust mechanical stability, capable of withstanding 5000 cycles of bending tests at a bending radius of 2.5 mm, achieved by scaling down the device dimensions.