Bi2Se3 nanosheets prepared by solvothermal method for high performance NIR photodetector

Bismuth selenide (Bi2Se3) nanosheets, a member of the AV-BVI (A = Sb, Bi, B = S, Se, Te) family of metal chalcogenide semiconductor materials, have a large surface area, a tunable bandgap that is dependent on the thickness of the atomic layer, and potential applications in photocatalysis, photothermal therapy, and photodetectors, among other fields. Here, we describe the synthesis of Bi2Se3 nanosheets using a simple solvothermal method, resulting in a smooth surface and a well-crystalline structure. The XRD results indicate that the Bi2Se3 nanosheets belong to the hexagonal crystal structure, with lattice constants of a = 0.4140 nm, b = 0.4140 nm, and c = 2.8636 nm. Bi2Se3 nanosheet photodetectors, which have a Schottky contact between the nanosheets and the electrodes, exhibit a notable light response to an 850 nm laser. The device displays a switch ratio of 50 when operated at a voltage of 0.6 V and an irradiance of 2.87 W/cm2 (@ 850 nm). The switching speed of the device was measured in terms of rise and decay times, measured to be 126 ms and 85 ms respectively. It is evident from the obtained results that high performance nanoscale photodetectors can be made efficiently from 2D Bi2Se3 nanosheets.