Abstract: Two-dimensional (2D) van der Waals heterostructure photodetectors have emerged as promising candidates for next-generation optoelectronic systems. However, their practical performance is often hindered by interfacial carrier recombination and inefficient charge extraction. Here, a high-performance CuInP₂Se₆/MoS₂ van der Waals heterojunction photodetector is reported that overcomes these challenges via engineered type-II band alignment and interfacial electric field modulation. Under 367 nm illumination, the device achieves an ultrahigh responsivity (R) of 907 A W^-1 and a fast photoresponse characterized by rise and decay times of 7.6 and 9.0 μs, respectively. These metrics surpass those of most previously reported MoS₂-based heterojunction photodetectors. Mechanistically, the type-II band alignment and built-in electric field synergistically facilitate efficient photogenerated carrier separation and suppress interfacial recombination, enabling superior photodetection performance. In addition, the device demonstrates optical OR logic functionality, capable of responding to either optical or gate stimuli, revealing its potential for logic-in-sensor architectures. Single-pixel imaging experiments further validate its excellent imaging capability, and convolutional neural network-assisted image recognition achieves an accuracy approaching 99 %, demonstrating the integration potential of logic-enabled phototransistors in intelligent vision systems. This work establishes a reconfigurable 2D optoelectronic platform that integrates fast photodetection with embedded logic and visual processing, offering a compelling strategy toward on-chip photonic computing and neuromorphic perception.

Key words: Fast photoresponse, CuInP₂Se₆, MoS₂, Heterojunction, Photodetector