A high-sensitivity epitaxial Ge/PbSe/CdSe/Bi₂Se₃ p⁺pBn⁺ barrier heterojunction for uncooled middle infrared detection

The inherent physical properties of common materials and fabrication techniques pose significant challenges for realizing low dark current and high sensitivity uncooled mid-wave infrared (MWIR) detectors. In this article, we propose and demonstrate a novel p⁺pBn⁺ barrier structure based on an epitaxial Ge/PbSe/CdSe/Bi₂Se₃ single crystal heterojunction to suppress dark current at room temperature. The experimental results indicate that a lower dark current of 8.49 mA cm⁻² is achieved for the p⁺pBn⁺ barrier photodetector. Moreover, this barrier device exhibits superior performance with a detectivity of 1.43 × 10¹⁰ cm Hz^1/2 W⁻¹ and a responsivity of 1.41 A W⁻¹ at room temperature. This work highlights the potential of PbSe-based p⁺pBn⁺ barrier structures for room temperature IR detection, providing both an industrialized technical solution and theoretical support for next-generation high performance uncooled MWIR detectors.