Electrostatically Gated p-n Junctions based on Encapsulated Few Atomic Layers of InSe

InSe, similar to Transition Metal Dichalcogenides (TMDs), has a layered crystallographic structure and can be exfoliated down to a single unit cell. It has been shown that InSe is a good candidate for photodetectors, covering the visible to the near-infrared region, with high photoresponsivities that are superior to those of other recently reported two-dimensional (2D) crystal based photodetectors. It has also been proved to be a promising candidate for field effect transistors (FET), with carrier mobilities exceeding 1000 cm²/V.s at room temperature. Here we evaluate the performance of p-n junctions that are based on few atomic layers of InSe encapsulated between h-BN on two separate back gates. The thickness of the InSe crystal ranges between 7 to 10 atomic layers with a near direct band gap φ of 1.3<φ<1.4 eV, which makes them a good candidate for photovoltaic applications. Moreover, due to smaller badgap of about 1.25 eV for bulkier crystals the devices are potential candidates for near infrared detection.