Electrically reconfigurable MoO3/InSe van der Waals heterojunctions

Van der Waals (vdW) heterojunctions formed by stacking different layers of two-dimensional atomic crystals with atomically sharp interface and versatile band alignment have been considered as promising candidates for construction of nanoelectronic and nanophotonic devices. Here, we demonstrate the electrically reconfigurable behavior in MoO3/indium selenide (InSe) vdW heterojunction with a type-III broken-gap band alignment. The electrical reconfigurability is enabled by the ambipolar transport property of InSe, which is achieved through the use of Pt as contact electrodes. By electrostatically doping the InSe, the reconfigurable MoO3/InSe heterojunctions can be converted between p-n and n(+)-n junctions. As a current rectifier, the MoO3/InSe heterojunction shows rectification ratios of similar to 10(7) and similar to 10(4) for forward and backward bias conditions, respectively. As a photodetector, the MoO3/InSe heterojunction shows stable photo-switching behavior with a similar to 10(5) on/off ratio and an ultralow dark current (approximate to 10 fA). The response time is measured to be 500 mu s and 300 mu s for rise and fall processes, respectively. These results highlight the role of MoO3 with high electron affinity in construction of vdW heterostructure with type-III band alignment and provide a new platform for high performance optoelectronic devices.