In this work, we report the photodetector properties of a vertically stacked heterostructure based on topological insulator Sb2Te3/n-Si. The high-quality Sb2Te3 thin films were grown on an n-Si substrate by the metal–organic chemical vapor deposition (MOCVD) technique. The fabricated Sb2Te3/n-Si heterostructure devices promise to work as an excellent rectification diode with an excellent rectification ratio (RR) (351.4 at ±3 V), under dark condition. The device shows remarkable photoresponse at a broad spectral near-infrared range of between 700 and 1100 nm. The maximum responsivity and detectivity of Sb2Te3/n-Si heterojunction diode 1600 mA/W and 10 Jones (at +3 V) were observed at 900-nm wavelength of incident light. The electronic and optical properties of the Sb2Te3 are evaluated using first-principle calculations based on density functional theory (DFT). The bandgap of Sb2Te3 was …