SCIENCE CHINA Materials2026
Dark-Current-Suppressed Semimetal-Based ZrTe3/CuInP2Se6 Heterostructure Photodetector for Information Encryption and Decryption
Photodetectors are critical components in modern optoelectronic systems, underpinning applications in optical communication, low-altitude economy, environmental monitoring, and national defense. Layered two-dimensional (2D) materials such as MoS2, WS2, black phosphorus (BP), and ReS2 have attracted extensive attention due to their remarkable electronic and optical properties, including facile mechanical exfoliation and tunable characteristics via thickness engineering. The absence of dangling bonds enables the construction of van der Waals (vdW) heterostructures free from lattice-matching constraints, promoting efficient charge transport, enhanced light absorption, and suppressed dark current. Among layered materials, semimetals such as graphene, PdTe2, MoTe2, and TaIrTe4 exhibit narrow or zero bandgaps, enabling ultrabroadband spectral responses from ultraviolet (UV) to terahertz (THz). ZrTe3, a layered gapless semimetal, demonstrates pronounced carrier transport features, including robust excitons and ultrafast carrier relaxation times, making it an ideal candidate for photodetection. However, pure ZrTe3-based photodetectors suffer from substantial dark current due to the absence of an energy bandgap, degrading signal-to-noise ratio and specific detectivity (D*). This work reports a high-performance broadband photodetector based on a ZrTe3/CuInP2Se6 heterostructure. By exploiting an asymmetric contact configuration that introduces a Schottky barrier, the device effectively suppresses dark current while enhancing photoresponse. The photodetector exhibits broad spectral sensitivity from UV to near-infrared (355–1177 nm), microsecond-level response speed, and high responsivity and specific detectivity. Beyond conventional photodetection, an optoelectronic information encryption-decryption application is demonstrated, where modulated light and bias voltage serve as dual input channels to encode and decode ASCII signals. This study resolves the challenge of high dark current in semimetal-based photodetectors and introduces a multifunctional platform for secure optoelectronic communication, highlighting the potential of ZrTe3 for next-generation photonic and quantum information technologies.