Photogating-assisted tunneling boosts the responsivity and speed of heterogeneous WSe2/Ta2NiSe5 photodetectors
Mingxiu Liu, Jingxuan Wei, Liujian Qi, Junru An, Xingsi Liu, Yahui Li, Zhiming Shi, Dabing Li, Kostya S. Novoselov, Cheng‐Wei Qiu, Shaojuan Li
Abstract
Abstract Photogating effect is the dominant mechanism of most high-responsivity two-dimensional (2D) material photodetectors. However, the ultrahigh responsivities in those devices are intrinsically at the cost of very slow response speed. In this work, we report a WSe 2 /Ta 2 NiSe 5 heterostructure detector whose photodetection gain and response speed can be enhanced simultaneously, overcoming the trade-off between responsivity and speed. We reveal that photogating-assisted tunneling synergistically allows photocarrier multiplication and carrier acceleration through tunneling under an electrical field. The photogating effect in our device features low-power consumption (in the order of nW) and shows a dependence on the polarization states of incident light, which can be further tuned by source-drain voltages, allowing for wavelength discrimination with just a two-electrode planar structure. Our findings offer more opportunities for the long-sought next-generation photodetectors with high responsivity, fast speed, polarization detection, and multi-color sensing, simultaneously.