Self-powered photovoltaic photodetector established on lateral monolayer MoS2-WS2 heterostructures

With the rapid development of modern semiconductor industry, power free or self-powered devices become an indispensable part in the electronic components and optoelectronic products. Epitaxial connected TMDs lateral heterojunctions with the maximum built-in potential at the hetero-interface offer fast separation of the photo-generated electron-hole (e-h) pairs without an external bias, which make them promising for self-powered devices. However, so far, the photovoltaic performance of such structures are rarely studied. Here, we report the photovoltaic light sensors based on individual monolayer MoS2-WS2 in-plane heterostructures that were created through a one-step synthesis strategy. The in situ second-harmonic generation (SHG) characterizations of this monolayer in-plane heterostructures directly demonstrate their underlying symmetry and high orientation. The photovoltaic photodetectors designed on individual MoS2-WS2 in-plane samples that operate in a self-powered mode (zero bias) exhibits a spectral responsivity (Rλ) of 4.36 mA/W and detectivity (D*) of 4.36 × 1013 Jones under 28.64 mW/cm2 @ 532 nm. The primary characteristics of the lateral heterostructure devices are attributed to the built-in potential at the interface. The initial self-powered light sensor in a monolayer heterostructures combined with the scalable growth can be further applied in other 2D heterostructures.