All‐Optical Modulation Photodetectors Based on the CdS/Graphene/Ge Sandwich Structures for Integrated Sensing‐Computing

Abstract In this manuscript, an all‐optical modulation photodetector based on a CdS/graphene/Ge sandwich structure is designed. In the presence of the modulation (near‐infrared) light, the Fermi level of the graphene channel shifts, allowing for the tuning of the visible light response speed as well as achieving a broad responsivity range from negative (‐3376 A/W) to positive (3584 A/W) response. Based on this, logical operations are performed by adjusting the power of the modulation light superimposed with the signal light. This facilitates more covert, all‐optical, high‐speed encrypted communication. The ultrahigh tunability and nearly symmetric positive and negative photoconductivity of all‐optical modulation photodetectors significantly enhance the computational capacity of neuromorphic hardware. The proposed device exhibits substantial advantages in applications requiring high fault tolerance for integrated sensing‐computing （ISC） and high‐resolution motion object recognition, providing insights for the development of next‐generation high‐bandwidth, low‐power‐consumption ISC devices.