Feiying Sun

Silicon avalanche photodiodes (APDs) exhibit excellent performance, including high speed, high responsivity, and high sensitivity in amplification of optical signals by virtue of avalanche multiplication effect, which holds considerable importance in weak light detection. Here, a systematic review on the research progress of Si‐APDs is presented. First, the typical device structures and working mechanisms of Si‐APDs are introduced. Subsequently, the optimizations of structural design and fabrication processes of Si‐APDs, as well as their impacts on the performance, are discussed. Finally, the present challenges and future development trends of Si‐APDs are prospected.

The exceptional adjustability and ambipolar behavior of graphene offer significant potential for next-generation optoelectronics, where the conductivity of graphene is primarily modulated by the interface field of heterojunction. However, interface defects, which are inevitably introduced during fabrication, severely limit the effectiveness of gate voltage modulation. Although the layer-by-layer transfer method can effectively enhance conductivity, it also raises the carrier concentration and impairs the symmetry of ambipolar characteristics. This work presents a stacked multi-gate graphene transistor in which synergistic modulation enables efficient regulation of channel conductivity while maintaining low carrier concentration. Simulations are carried out to analyze how mobility, doping concentration, and the number of stacking layers influence the modulation of conductivity. Experimentally, a three-layer stacked graphene structure with distributed source and drain electrodes is fabricated. The device exhibits pronounced ambipolar transfer characteristics and demonstrates a clear improvement in transconductance compared to its conventional one-layer graphene counterpart. This research offers a feasible design strategy for high-performance, vertically integrated graphene-based electronic devices.

Serving as the “eyes” and “ears” of the Internet of Things, optical and acoustic sensors are the fundamental components in hardware systems. Nowadays, mainstream hardware systems, often comprising numerous discrete sensors, conversion modules, and processing units, tend to result in complex architectures that are less efficient compared to human sensory pathways. Here, a visual-audio photodetector inspired by the human perception system is proposed to enable all-in-one visual and acoustic signal detection with computing capability. This device not only captures light but also optically records sound waves, thus achieving “watching” and “listening” within a single unit. The gate-tunable positive, negative, and zero photoresponses lead to highly programmable responsivities. This programmability enables the execution of diverse functions, including visual feature extraction, object classification, and sound wave manipulation. These results showcase the potential of expanding perception approaches in neuromorphic devices, opening up new possibilities to craft intelligent and compact hardware systems.