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-MnBi 2 Te 4 (MBT) -metal structures at room temperature. By integrating MBT and Bi 2 Te 3 into van der Waals structures, the heterostructure device can reduce dark current and have excellent sensitivity at room temperature. Especially, MBT/Bi 2 Te 3 photodetectors have a fast response time (<1 μ s) and low noise equivalent power <0.5 nW Hz −1/2 at self-powered mode due to photothermoelectric conversion. The MBT/Bi 2 Te 3 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.