Performance enhancement of InSnZnO thin-film transistors by modifying the dielectric-semiconductor interface with colloidal quantum dots

Thin film transistors (TFTs) with InSnZnO (ITZO) and Al2O3 as the semiconductor and dielectric layers, respectively, were investigated, aiming to elevate the device performance. Chemically synthesized CuInS2/ZnS core/shell colloidal quantum dots (QDs) were used to passivate the semiconductor/dielectric interface. Compared with the pristine device, the device with the integrated QDs demonstrates remarkably improved electrical performance, including a higher electron mobility and a lower leakage current. Moreover, the integration of QDs largely mitigates hysteresis in the bidirectional transfer characteristics of the device. Improved negative bias stress stability is also observed in the device with QDs. The performance enhancement is ascribed to the reduction of the trap states induced by the defects in Al2O3, and the screening of electrical dipoles at the Al2O3/ITZO interface. This work proposes a new strategy to passivate the semiconductor/dielectric interface, which not only improves TFT performance, but also holds potential for optoelectronic applications.