Topological insulator MnBi₂Te₄ and its van der Waals heterostructure for sensitive room-temperature terahertz photodetection

Dirac fermions are a distinctive feature of topological insulators (TIs) due to the existence of topologically protected surface states, making TIs a promising choice for long-wavelength photodetection. However, TIs-based photodetection often suffers from significant dark current. This paper demonstrates broadband detection through the direct generation of photocarriers in metal-MnBi2Te4 (MBT) -metal structures at room temperature. By integrating MBT and Bi2Te3 into van der Waals structures, the heterostructure device can reduce dark current and have excellent sensitivity at room temperature. Especially, MBT/Bi2Te3 photodetectors have a fast response time (<1 mu s) and low noise equivalent power <0.5 nW Hz(-1/2) at self-powered mode due to photothermoelectric conversion. The MBT/Bi2Te3 photodetector detects low-energy photons through the hybrid integration of new low-dimensional materials that will be already suitable for imaging applications, further emphasizing the unique advantages of TIs in the field of terahertz technology.