2D Ti3C2 nanoflakes anchored ZnO photodetector with substantially improved deep-ultraviolet photoresponse and on/off ratio

Deep ultraviolet photodetectors (deep-UV PDs) are promising for multiple applications due to their high detecting accuracy and sensitivity in the absence of background sunlight disturbance. By alloying, the bandgap of ZnO can be extended for deep-UV optoelectronics . However, it is limited by the solubility and the crystal quality degradation for a high-component alloy, which hinders the practical applications. In this work, we simply use the 2D Ti 3 C 2 nanoflakes to anchor on ZnO surface to enhance the deep-UV band absorption. Moreover, van der Waals heterojunctions formed at the dispersed Ti 3 C 2 /ZnO interfaces create surface depletion and passivation, which suppresses the dark current and enhances the photocurrent simultaneously. As a result, the Ti 3 C 2 nanoflakes anchored ZnO PD shows enhanced photoresponse in the entire UV region. Particularly, in the deep-UV range this enhancement is much more significant, with a peak light to dark ratio, EQE , responsivity and detectivity of 1.64 × 10 4 , 128.3 mA/W, 66.3% and 5.7 × 10 11 Jones respectively achieved at 240 nm light illumination, which is enhanced by 284, 72, 74 and 55 times respectively compared to the pristine ZnO PD. This work provides a newly non-alloyed strategy to broaden ZnO-based deep-UV, high-performance photodetection applications.