Interface Engineering for Hysteresis-Free, High-Performance, and Stable a-IGO Thin-Film Transistors

The instability of oxide thin-film transistors (TFTs) remains a critical concern that demands attention. Herein, interface engineering was employed to enhance the performance of amorphous indium gallium oxide (a-IGO) TFTs. The Al2O3 sandwich-encapsulation a-IGO TFTs demonstrate outstanding electrical characteristics and remarkable stability, evidenced by an average field-effect mobility of 33.1 cm $^{{2}} \cdot $ V $^{-{1}}$ s $^{-{1}}$ , subthreshold swing of 0.19 V/dec, and an on/off ratio of $10^{{7}}$ across ten devices. Notably, the most astonishing feature lies in its ability to achieve an exceptionally low hysteresis of merely 0.04 V. Besides, after enduring 3600 s of positive bias stress (PBS) (+2 V) and negative bias stress (NBS) (−2 V), the threshold voltage shifts by insignificant amounts of 0.1 and 0.08 V, respectively. Moreover, the device’s longevity in ambient conditions is noteworthy, as evidenced by a mere 1.2% decrease in mobility after 60 days of exposure, highlighting its exceptional environmental stability. Those enhancements in device performance can be attributed to the defect self-compensation effect, which leads to the reduction of a-IGO thin-film defects in sandwich-structured devices. The results indicate that the sandwich-encapsulated IGO TFTs emerge as a highly promising candidate for the next-generation display industry.