Substrate Heating and Multi-Stage Low-Temperature Annealing for High-Performance Indium-Oxide Thin-Film Transistors and Phototransistors

In recent years, indium-oxide thin-film transistors (IOTFTs) have been developed with high electron mobility, low power consumption, and good environmental stability. A major challenge in current IOTFTs research lies in developing high-performance devices through low-temperature processes while simultaneously expanding their functionality into photonic applications. Our study proposes a low-temperature annealing method for high-performance IOTFTs fabrication, combining substrate heating and a multi-stage annealing process. The optimized device exhibits a device mobility of 47.99 cm2/V·s, a threshold voltage of 2.8 V, a subthreshold swing (SS) of 742.83 mV/dec, and good stability under bias stress tests. Building upon the IOTFTs, we extend the functionality to photonic applications by integrating poly[[2,3,5,6-tetrahydro-2,5-bis(2-octyldodecyl)-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl]-2,5-thiophenediylthieno[3,2-b]thiophene-2,5-diyl-2,5-thiophenediyl] (DPPDTT) photoresponsive layer, achieving a phototransistor with responsivity of 3.7 A/W and detectivity of 5.86 × 1011 Jones at 850 nm near-infrared light. This work provides a new approach for fabricating high-performance indium-oxide thin-film transistors and phototransistors with low-temperature annealing.