Room temperature large photoresponse in p-n heterojunction composed of WSe2 and 2D electron gas at LaAlO3/KTaO3 interface.

The heterostructures combining 2D layered material and two-dimensional electron gas (2DEG) at the surface or interfaces of complex oxides may exhibit abundant and interesting physical properties. In this paper, we report the development and photoelectrical properties of a p-n heterojunction composed of a p-type 2D layered material WSe2 and n-type 2DEG at the LaAlO3/KTaO3 interface. The WSe2 flake was first fabricated by mechanical exfoliation and then integrated with 2DEG at the LaAlO3/KTaO3 interface obtained using pulsed laser deposition. The WSe2/2DEG heterostructure shows good rectifying behavior with a low leakage current at room temperature. Additionally, compared with oxide 2DEG, the WSe2/2DEG heterostructure exhibits greatly enhanced visible-light photoresponse. The results imply that the 2D heterostructures based on disparate material systems can be realized and demonstrate potential applications in nanoscale electronics and optoelectronics, which are of great scientific and technological significances. [ABSTRACT FROM AUTHOR]