Self-Driven Photodetector and Ambipolar Transistor in Atomically Thin GaTe-MoS₂ p–n vdW Heterostructure

Abstract

Heterostructure engineering of atomically thin two-dimensional materials offers an exciting opportunity to fabricate atomically sharp interfaces for highly tunable electronic and optoelectronic devices. Here, we demonstrate abrupt interface between two completely dissimilar material systems, i.e, GaTe-MoS 2 p−n heterojunction transistors, where the resulting device possesses unique electronic properties and self-driven photoelectric characteristics. Fabricated heterostructure transistors exhibit forward biased rectifying behavior where the transport is ambipolar with both electron and hole carriers contributing to the overall transport. Under illumination, photoexcited electron−hole pairs are readily separated by large built-in potential formed at the GaTe−MoS 2 interface efficiently generating self-driven photocurrent within <10 ms. Overall results suggest that abrupt interfaces between vastly different material systems with different crystal symmetries still allow efficient charge transfer mechanisms at the interface and are attractive for photoswitch, photodetector, and photovoltaic applications because of large built-in potential at the interface.

Various Structures of 2D Transition‐Metal Dichalcogenides and Their Applications

“…In MoS 2 /WSe 2 heterostructures, diode‐like current rectification could be observed for the combination of holes in WSe 2 with electrons in MoS 2 when forward bias is applied, while the current is stopped in reverse bias. Indeed, such rectifying performance is quite a common property in atomic‐thickness heterostructures ( Figure a) . Moreover, the unique combination and separation of carriers, such as long‐lifetime excitons and ultrafast charge transfer in TMDs heterostructures, have also been demonstrated .…”

Self‐Powered Photodetectors Based on 2D Materials

“…The mechanical stacking method is the easiest way to construct any 2D vertical heterostructure. For example, Yang et al fabricated a transistor based on the GaTe–MoS 2 vertical p–n heterojunction, which transferred a p‐type GaTe to an n‐type MoS 2 wafer by dry stamping to form a vertical 2D p–n heterojunction, as shown in Figure b. The GaTe–MoS 2 p–n heterojunction exhibits better electronic and optoelectronic properties than a single component and exhibited unique electron transport and excellent photoresponsive properties.…”

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.…”