Tunable Polarity Behavior and Self‐Driven Photoswitching in p‐WSe₂/n‐WS₂ Heterojunctions

Abstract

Van der Waals (vdW) p-n heterojunctions consisting of various 2D layer compounds are fascinating new artificial materials that can possess novel physics and functionalities enabling the next-generation of electronics and optoelectronics devices. Here, it is reported that the WSe2/WS2 p-n heterojunctions perform novel electrical transport properties such as distinct rectifying, ambipolar, and hysteresis characteristics. Intriguingly, the novel tunable polarity transition along a route of n-"anti-bipolar"-p-ambipolar is observed in the WSe2/WS2 heterojunctions owing to the successive work of conducting channels of junctions, p-WSe2 and n-WS2 on the electrical transport of the whole systems. The type-II band alignment obtained from first principle calculations and built-in potential in this vdW heterojunction can also facilitate the efficient electron-hole separation, thus enabling the significant photovoltaic effect and a much enhanced self-driven photoswitching response in this system.

Tuning Coupling Behavior of Stacked Heterostructures Based on MoS2, WS2, and WSe2

“…In type II heterojunctions, the CBM and VBM reside in two separate materials. Moreover, the type II band alignment and built-in potential in the heterojunctions can facilitate the photoexcited electron-hole separation and lead to an enhanced photoswitching performance compared to that in MoS 2 WS 2 and WSe 2 26. For example, in MoS 2 -WS 2 heterostructure, due to the type-II band alignment, photoexcited electrons and holes will relax (dashed lines in Fig.…”

Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

“…Van der Waals (vdW) heterostructures composed of 2D layered materials have been attempted intensively recently due to the novel physical properties covering a wide range of electronic, optical, and optoelectronic systems 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242. Jo and co‐workers130 synthesized polymorphic 2D tin‐sulfides of either p‐type SnS or n‐type SnS 2 via adjusting hydrogen during the process.…”

Toward High‐Performance Photodetectors Based on 2D Materials: Strategy on Methods

“…Due to the lack of dangling bonds on the surfaces of vdW materials, vertical heterostructures can be fabricated with high‐quality heterointerfaces without the consideration of lattice mismatch and Fermi‐level pinning that often occurs at the metal and semiconductor interface . In contrast to lateral heterostructures, benefiting from the near‐perfect optical transparency and the unique electronic properties of graphene, such vertical vdW heterostructures can realize a large, scalable active area and a short, atomically thin charge‐extraction channel, potentially achieving both efficient and fast photodetection. It is interesting to mention that this method can meet the challenge of developing photodetectors simultaneously possessing a large active area, a high internal efficiency, and a fast response time.…”