A silver nanoparticle (AgNP)-loaded Bi2Se3 topological insulator p-n heterojunction photodiode for a near-infrared (NIR) photodetector

Near-infrared (NIR) photons are expanding advanced applications in optoelectronics. However, while 2D materials like graphene offer an attractive route for NIR photodetection, the alternative for high-performance NIR detection is still evolving. Hence, solution-processed n-Bi2Se3 /p-Si-based 2D heterojunction photodiodes have been fabricated here and used for high-performance NIR detection. Further, we report high photoresponsivity of 248 mA W−1 at 1100 nm, high external quantum efficiency of 22, 23 and 28% for Ag-loaded (at 5, 7.5 and 10%) Bi2Se3 and good stability. The chemical states of Bi2Se3 and Ag are detected using the core-level spectra of x-ray photoelectron spectroscopy. Photoresponse I–V characteristics are investigated under both dark and illumination; the high photocurrent achieved for Ag-loaded Bi2Se3 and the increase in the forward photocurrent under both dark and bright conditions are reported. The temporal photoresponse curve confirms the good stability (photoswitching behavior) and reproducibility with a response time of 0.74 s and a decay time of 0.18 s. Therefore, these unique performance and device parameters of a manufactured photodiode strongly recommend as a potential heterojunction photodiode for an NIR photodetector.