Dual-quadrant photodetection in topological insulator and silicon-based heterojunction (n-Bi₂Te₂Se/p-Si)

Bi₂Te₂Se is a unique topological insulator (TI) with immense potential for spintronics and wideband photoelectric devices. Integration of Bi₂Te₂Se thin TI film was done with p-type Silicon (Si) substrate to formulate a lateral heterojunction. The transport properties of the n-Bi₂Te₂Se/p-Si heterojunction were studied and electrical characterization was done by I-V measurement. The electrical results confirmed the p-n heterojunction diode formation. The n-Bi₂Te₂Se/p-Si heterojunction diode had a good rectification ratio (~326 at ± 2 V) and a figure of merit under dark conditions. The photoelectric measurement of the n-Bi₂Te₂Se/p-Si heterojunction was done for a broad spectral range and incident power. Excellent dual-quadrant photodetection was observed for n-Bi₂Te₂Se/p-Si heterojunction from visible to near-infrared range with optimum performance at 900 nm incident light wavelength. Good responsivity and detectivity of 19.06 A/W, 8 ×10¹¹ Jones at forward bias (+2 V) and 12.64 A/W, 7.72 ×10¹¹ Jones at reverse bias (- 2 V) was observed at 900 nm wavelength of incident light. The device also had a convincing photoconductive gain of 26.31 (+2 V). The study provides a significant insight into the transport properties of the next-generation topological insulator/Si heterojunction-based photodetectors.