Room‐Temperature, Flexible MnBi 2 Te 4 /As 2 Te 3 Thin‐Film Heterojunction Array Photodetectors

Three‐dimensional (3D) topological insulators (TIs) are theoretically promising candidates for broadband photodetection across the visible‐to‐infrared regions because of their stable physical properties and strong light absorption. In this study, MnBi 2 Te 4 /As 2 Te 3 thin‐film heterojunction array photodetector was fabricated, exhibiting a rapid and broadband photoresponse within 450–1550 nm. The thin films were prepared using a cost‐effective thermal evaporation method, offering a new route for fabricating large‐scale array devices. The device demonstrated a response time of less than 80 μs, an optimized responsivity of 4.75 × 10 −2 A W −1 , and excellent mechanical flexibility. Its performance decreased by less than 9.53% under 50% bending strain and remained stable after 5000 bending cycles. These results demonstrate that heterojunction photodetectors based on 3D TIs combined with other materials hold significant potential for flexible optoelectronic applications.