Flexible InSnZnO Thin Film Phototransistors for Deep Ultraviolet Detection

Three-terminal phototransistors, with a regular photoconductor and the flexibility to control channel carriers, have been considered to be an alternative solution for the improvement in photodetector (PD) performance. This work first demonstrates ZnO-based deep ultraviolet (DUV) phototransistors prepared by co-sputtering. The response of the InSnZnO (ITZO) phototransistor to near-ultraviolet (NUV) light is effectively suppressed at low levels by the passivation layer that is modified with diethylamino hydroxybenzoyl hexyl benzoate. Moreover, the fabricated DUV phototransistors exhibited excellent electrical characteristics and competitive DUV photodetection performance, such as a low threshold voltage of 0.8 V, a high responsivity of 416 AW $^{-{1}}$ , and a considerable rejection ratio of ${3.26}\times {10}^{{3}}$ at $\text{V}_{\text {gs }}= {0}$ V. Unlike a-Ga ₂ O ₃ phototransistors, the ITZO phototransistors exhibit a more considerable carrier mobility (30.7 cm $^{{2}}\,\,\text{V}^{-{1}}\text{s}^{-{{1}}}$ ), which means this sensor could work as the sensing part and compose the readout circuit, thereby simplifying the process of the sensor system.