Enhanced photosensitivity in a hybrid WSe2/2DEG heterojunction using a buried TiO2 photosensitive layer

Abstract In this study, we integrated the wide-bandgap material TiO2 as a photosensitive layer with the WSe2/two-dimensional electron gas (2DEG) heterostructure, creating a hybrid WSe2/TiO2/2DEG heterojunction. This hybrid structure significantly improves the device's photosensitivity, exhibiting a high rectification effect and a switching ratio of 103. The photodetector shows excellent performance with a high responsivity of 0.61 A/W, a large detectivity of up to 1.1×1011 Jones at 405 nm, along with an ultra-fast photoresponse speed. The buried TiO2 channel allows photogenerated electrons to easily flow through the reduced barrier at the depleted region. This hybrid heterojunction holds promise for the development of high-performance photoelectric devices.