Flexible, solution-processed, indium oxide (In2O3) thin film transistors (TFT) and circuits for internet-of-things (IoT)

Abstract

Over the last decade, novel approaches to explore low voltage flexible devices and low power flexible circuits are being widely researched by the scientific community. To realize the true potential of energy thrifty Internet-of-Things (IoT) objects, low power circuits and hence their low-voltage operating devices are a paramount prerequisite, especially when their power is constrained by autonomous energy scavenging. At present, through advanced manufacturing processes, silicon-based semiconductor devices are powering the modern electronics industry. However, processing temperatures are inhibiting them from flexible and printed electronics, as well as being too costly for scalability to the trillions of IoT objects anticipated. Therefore, development of solution-processed metal oxide semiconductors creates huge opportunities for IoT and wearables. Here, flexible solution-processed indium oxide (In2O3) thin film transistors (TFT) and inverter circuits with low operating voltage are reported. The operating voltage of the TFTs is ≤ 3 V with threshold voltage (Vth) 0.82 V, on/off ratio 105 and extracted mobility (μ) in saturation regime is 14.5 cm2/V·s. The gain of the inverter at VDD 1, 2 and 3 V was determined to be 10, 22 and 32 respectively. Furthermore, measured transconductance (gm) and subthreshold swing (S) are found to be 140 μS and 0.22 V/dec, respectively.