Two-Dimensional Bi₂Se₃/MoSe₂ Heterostructure for Photodetection Applications

In this work, we have experimentally fabricated a MoSe₂/Bi₂Se₃-based type-II van der Waals (vdW) heterojunction photodetector (PD) suitable for detecting optical signals between 400 and 1000 nm. This PD shows excellent performance metrics such as a peak responsivity of 13.35 A/W and a detectivity of 5.7 × 10¹³ Jones at 400 nm. Also, the fabricated PD exhibited an ultrahigh external quantum efficiency of 4038% at 400 nm with rise and fall times of 105 and 166 ms, respectively. The built-in potential at the heterojunction facilitated excellent separation and transport of the photogenerated electron-hole pairs through suitable energy band diagrams. Also, various Schottky diode parameters of the device have been extracted from the measured I-V characteristics. Using the modeled parameters, I-V characteristics were redrawn and compared with the measured values. Between 0 and 5 V, the modeled I-V characteristics showed minimum and maximum errors of 0.57% and 6.21%, respectively.