Few-layer WSe 2 lateral homo- and hetero-junctions with superior optoelectronic performance by laser manufacturing

Lateral hetero-junctions are considered as potential candidate for building blocks in modern electronics and optoelectronics, however, the construction of which remains a challenge. In this work, by using a laser-assisted manufacture technique, WSe2/WO3−x hetero-junction and monolayer/trilayer WSe2 homo-junction with Schottky diode like behavior are fabricated, both of which present competitive performance for photodetection and power generation in a wide range of wavelengths from ultraviolet to infrared, with maximum photoresponsivity of 10 A/W, external quantum efficiency of 14%, and power conversion efficiency of 1.3%. Combined with Kelvin probe microscopy and electrical transport measurements, it is demonstrated that the barrier-induced built-in electric field at WSe2/WO3−x interface, and the energy band discontinuities at the monolayer/trilayer WSe2 interface facilitate the separation of photo-generated electron-hole pairs. Our work provides a solid step towards the controllable construction of lateral junctions by laser-assisted manufacture for exploiting van der Waals materials-based novel electronic and optoelectronic applications.