Piezo‐Phototronic Effect in 2D α‐In₂Se₃/WSe₂ van der Waals Heterostructure for Photodetector with Enhanced Photoresponse

Abstract 2D materials offer a platform that allows the creation of flexible functional devices with various properties due to their extraordinary properties. In this work, the influence of piezo‐phototronic effect on a flexible α‐In₂Se₃/WSe₂ van der Waals (vdW) heterostructure is investigated and the strain‐regulated photoresponse of the device is examined. Owing to the noncentrosymmetric structure of III–VI compound α‐In₂Se₃, the strain‐induced piezo‐potential modulates the band slope near the P‐N junction interface, improving the transfer characteristics and separation efficiency of photogenerated electron–hole pairs by piezo‐phototronic effect. With applying the tensile strain of 0.433%, the photocurrent of the photodetector can be enhanced by about 18 times. Furthermore, the photodetectors present remarkable photoresponsivity and detectivity that can reach up to 4.61 × 10⁵ A W⁻¹ and 4.34 × 10¹⁴ Jones, respectively. These results indicate that the piezo‐phototronic effect can be introduced to facilitate strain‐modulated vdW P‐N heterojunction photodetector, which provides an insightful design of 2D material‐based vdW heterostructure toward high‐performance flexible optoelectronics.