Performance of Topological Insulator (Sb2Te3)-Based Vertical Stacking Photodetector on n-Si Substrate

— 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 7.48 × 1010 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 found to be 0.12 eV. The optical properties of Sb2Te3 were calculated based on DFT and random phase approximation. The absorption coefficient shows that Sb2Te3 absorbed the light in a broadband spectral region and maximum absorption at 905 nm, which is in good agreement with the experimental results.