Pronounced photogating effect in atomically thin WSe2 with a self-limiting surface oxide layer

摘要: The photogating effect is a photocurrent generation mechanism that leads to marked responsivity in two-dimensional (2D) semiconductor-based devices. A key step promote the 2D semiconductor integrate it with high density of charge traps. Here, we show self-limiting surface oxides on atomically thin WSe2 can serve as effective electron traps facilitate p-type photogating. By examining gate-bias-induced threshold voltage shift transistor based single-layer oxide, trap and rate oxide are determined be >1012 cm−2 and >1010 cm−2 s−1, respectively. White-light illumination an oxide-covered 4-layer photocurrent, magnitude which increases hole mobility. During illumination, evolves timescale seconds, portion current persists even after illumination. These observations indicate photogenerat...