Quantum-Inspired Thin Film Based Self-Powered Dual-Band Photodetection on a Topological Insulator Bi2Te3/p-GaN Heterojunction

Abstract Highly sensitive and self-powered photodetection is a key requirement for applications in space communication, flame sensing, bioimaging, and environmental monitoring. The integration of topological insulator (TI) materials with wide-bandgap (WBG) semiconductors offers an effective platform for high-performance self-powered ultraviolet (UV) and near-infrared (NIR) photodetection due to the efficient carrier transport and strong light–matter interactions. Despite the remarkable topological and optical properties of TIs, comprehensive and systematic studies of their magnetotransport and photodetection behavior in heterojunctions with WBG GaN are relatively underexplored. Here, we have deposited Bi2Te3 thin films on p-GaN/sapphire (0001) substrates by DC magnetron sputtering and investigated their magnetotransport and dual-band UV and NIR photodetector (PD) properties. Raman spectroscopy and high-resolution X-ray diffraction analyses revealed the formation of the rhombohedral crystalline Bi2Te3 thin films, while X-ray photoelectron spectroscopy confirmed their chemical states. Atomic force microscopy characterization showed that the truncated triangular and hexagonal quintuple-layered-like formations are strongly connected to one another, forming a continuous network exhibiting distinct crystalline growth. The magneto-transport analysis reveals weak antilocalization in Bi2Te3/p-GaN, with the Hikami–Larkin–Nagaoka coefficient “α”; value of –2 at 2 K. The “α” value indicates more than two decoupled transport channels arising from the topological surface states (TSS) at the top and bottom surfaces of Bi2Te3. The fabricated metal-semiconductor-metal-based Bi2Te3/p-GaN PD exhibited self-powered operation with a responsivity of ∼1.51 × 103 mA/W and ∼0.67 mA/W under UV and NIR illumination, respectively. It achieves UV photoresponsivity of ∼4.91 × 102 A/W at 5 V bias, which represents an ∼5.64 × 102-fold enhancement over the bare p-GaN-based PD. This remarkable enhancement in PD performances is attributed to the synergistic effects, i.e., strong built-in electric field at the heterojunction and TSS of TIs on p-GaN for the development of next-generation self-powered and high-responsivity dual-band photodetection applications.