Water- and DUV-induced self-passivation for In2O3 nanofiber field effect transistor

For field effect transistors (FETs) based on electrospun oxide nanofibers, the electrical stability can be deteriorated by high-temperature annealing treatment. In this work, the self-passivation of an In2O3 nanofiber FET is achieved by the consequent thermal treatment, water treatment, and deep ultraviolet (DUV) irradiation, and the FET is named as a TWD (thermal treatment-water treatment-DUV irradiation)-device. For comparison, the devices treated by thermal treatment and by thermal + water treatment were also fabricated and abbreviated as a T-device and a TW (thermal treatment-water treatment)-device, respectively. From the transfer characteristics of the T-, TW-, and TWD-devices, the electrical performance is first degraded by water treatment and then recovered after DUV irradiation. The positive bias stress test confirms the stability enhancement after TWD treatment, indicating the achievement of the self-passivated FET based on In2O3 nanofibers. The excellent electrical stability is owing to the structural relaxation and the removal of trap sites such as oxygen vacancy and hydroxide. Integrated with the high-k ZrO2 dielectric, the TWD-In2O3/ZrO2 FET exhibits further improved electrical performance, including a mobility of 3.35 cm2/V s and a high on/off current ratio of 107.