Ultrafast charge transfer in MoS ₂ /WSe ₂ p–n Heterojunction

Abstract

Atomically thin and sharp van der Waals heterojunction can be created by vertically stacking p-type monolayer tungsten diselenide (WSe 2 ) onto n-type molybdenum disulfide (MoS 2 ). Theory predicts that stacked MoS 2 and WSe 2 monolayer forms type II p-n junction, creating a built-in electric field across the interface which facilitates electron-hole separation and transfer. Gaining insights into the dynamics of charge transfer across van der Waals heterostructure is central to understanding lightphotocurrent conversion at these ultrathin interfaces. Herein, we investigate the exciton dissociation and charge transfer in a MoS 2 /WSe 2 van der Waals hetero-structure. Our results show that ultrafast electron transfer from WSe 2 to MoS 2 take place within 470 fs upon optical excitation with 99% charge transfer efficiency, leading to drastic photoluminescence quenching and decreased lifetime. Our findings suggest that van der Waals heterostructure may be useful as active components in ultrafast optoelectronic devices.

Gate-Tunable WSe2/SnSe2 Backward Diode with Ultrahigh-Reverse Rectification Ratio

“…We first study the degree of charge transfer across WSe2/SnSe2 heterojunction owing to the highly staggered type II band alignment ( Figure 1a) 46,47 . We employ photoluminescence (PL)…”

Photodetectors based on junctions of two-dimensional transition metal dichalcogenides

“…This implies MoS2/WSe2 heterojunction could be have big potential for high-speed photodetectors. [82] Photoelectric properties of lateral heterojunctions based on only TMDCs. In addition to vertical heterojunctions, lateral 2D heterojunctions have also emerged.…”

Lateral multilayer/monolayer MoS2 heterojunction for high performance photodetector applications

“…Vertical junctions such as WSe 2 /MoS 2 16 and black phosphorus/MoS 2 17 can be formed by stacking two different 2D materials through Van der Waals forces. However, the band offsets between different TMDCs are pivotal, which could inhibit carrier transport.…”