Oxygen-Engineered TeO_X for Cryogenic p-Channel Thin-Film Transistors

The advancement of cryogenic electronics for space exploration and quantum computing is critically limited by the absence of reliable p-channel transistors, which often suffer from low on-off ratios and significant hysteresis at low temperatures. Here, we report high-performance, wafer-scale p-type tellurium oxide (TeO_X) thin film transistors (TFTs) fabricated via e-beam evaporation and low-temperature annealing (< 150 °C). Through precise modulation of oxygen content, we achieve a high field-effect mobility of 30 cm ² V^-1s^-1 and a record-high on-off ratio of 10¹⁰ at 10 K, with negligible hysteresis and high reliability. The exceptional performance is attributed to bandgap engineering via oxygen composition—which effectively suppresses the off-state current—and to enhanced crystallinity achieved through optimized annealing. This breakthrough underscores the potential of oxygen-modulated TeO_x for energy-efficient and highly reliable CMOS integrated circuits in extreme cryogenic environments.