High‐Performance Photodetection in MoSe ₂ /Bi ₂ Se ₃ /MoTe ₂ Dual Heterostructure Enabled by Topological Interlayer Design

Abstract Van der Waals (vdWs) heterostructures based on 2D materials demonstrate great potential in high‐performance photodetectors. Strategic integration of topological insulators into van der Waals heterostructures provides new degrees of freedom for photocarrier generation, separation, and collection processes, leading to enhanced device metrics. Here, a MoSe ₂ /Bi ₂ Se ₃ /MoTe ₂ heterotrilayer photodetector is fabricated, where the Bi ₂ Se ₃ interlayer serves dual functions: i) as a dirac‐cone‐enabled ultrafast charge transport highway and ii) as a band alignment modulator creating built‐in fields in the MoSe ₂ /Bi ₂ Se ₃ and Bi ₂ Se ₃ /MoTe ₂ interfaces, respectively. Through Kelvin probe force microscopy, the band alignment in MoSe ₂ /Bi ₂ Se ₃ /MoTe ₂ is revealed. Under 532 nm illumination with a power density of 439.2 µW mm ^{− 2} , the fabricated device exhibits exceptional performance metrics: a high responsivity (R) of 4.61 A W ⁻¹ , an external quantum efficiency (EQE) of 1070%, and a specific detectivity (D ^* ) of 2.29 × 10 ¹¹ Jones. The transient photoresponse demonstrates rapid response/recovery time of 4.0/4.1 ms, respectively. Furthermore, spectral response measurements confirm broadband detection capabilities spanning from the visible to near‐infrared range of 400–1550 nm. These metrics surpass conventional MoSe ₂ /MoTe ₂ devices by a near four‐fold higher photocurrent along with approximately twelve‐fold enhancements in R, EQE, and D ^* . This work provides a promising strategy for designing high‐performance photodetectors.