Heterostructure‐Based Self‐Powered 2D Photodetectors: Devices and Applications

ABSTRACT 2D materials (2DMs)‐based self‐powered photodetectors (SPPDs) represent a new paradigm for low‐power optoelectronics, as they achieve battery‐free operation and simplified device architectures. The self‐powered properties of 2DM‐SPPDs are generally induced through two fundamental mechanisms: 1) symmetry‐breaking, which creates asymmetric built‐in electric fields via PN junctions, asymmetric contacts, electrodes, or thickness; 2) multi‐physical coupling, which leverages piezo‐optoelectronic, ferro‐optoelectronic, photo‐thermoelectric, or other effects to provide additional driving forces for carrier separation and functionality. In this review, we present a comprehensive review and performance comparisons of 2DM‐SPPDs arising from these two distinct mechanisms. Typical application scenarios based on 2DM‐SPPDs, including imaging, optical communications, and bionic and wearable optoelectronics are summarized and critically compared with conventional Si‐based photodetectors. Finally, we provide the prospects of 2DM‐SPPDs, highlighting that challenges remain in bandwidth‐responsivity trade‐offs, wafer‐scale growth, packaging and bonding, CMOS compatibility, and testing standardization. We anticipate that this perspective will serve as a valuable reference to guide future research efforts and accelerate the industrial deployment of 2DM‐SPPDs.