Polarization-selective photodetector based on topological insulators for secure optical communications and sensing applications

This study explores a novel photodetector based on the binary topological insulator bismuth selenide (Bi2Se3), leveraging its unique surface conduction properties and high surface-to-volume ratio. Unlike previous research focusing on heterojunctions, we investigate the intrinsic polarization selectivity of Bi2Se3. Our experimental results demonstrate a stable responsivity of 22.6 A/W under a -0.6 V bias voltage with 860 nm laser illumination and a polarization-sensitive switching of 10.9 dB. The device exhibits sensitivity across the near-infrared spectrum, showcasing its potential for applications in low-noise imaging, environmental monitoring, and optical communication. Additionally, the high polarization sensitivity paves the way for promising applications in non-destructive material assessment, hardware security enhancement, and secure communication systems.