Bulk induced photo-current in topological insulating materials (Bi₂Se₃/Si) heterojunction for highly responsive photodetectors

Studies of quintuple layers (QLs) dependent transport can shed light on the bulk and surface states because bulk and surface transport parameters have different QL dependencies. The QL dependency of material properties in Bi₂Se₃ reported in this study demonstrates that the QL is a parameter that may be adjusted to control and possibly optimise the bulk properties of Bi₂Se₃ thin films. We have explored the transport properties of the topological insulator Bi₂Se₃ thin films as a function of thickness. The resistivity-temperature curve reveals that as the thickness increases, the amount of bulk contribution to the conduction increases, indicating that thicker QL materials exhibit a superior photocurrent. The electronic properties have also been incorporated in support of the experimental findings, which were calculated using Quantum Espresso codes for the density functional theory. Using Bi₂Se₃/Si heterostructure, a photodetector with a robust response to 1100 nm irradiance is fabricated, revealing better optoelectronic properties for thicker QL.