Comparison of Photogating and Schottky Effects in Silicon–Graphene Hybrid Photodetectors for Imaging

Abstract Silicon–graphene hybrid photodetectors represent a promising platform by combining graphene’s high carrier mobility and pronounced electrostatic sensitivity with silicon’s superior light absorption capability. However, systematic comparisons of different detection mechanisms in such hybrids remain limited, making it challenging to identify the optimal architecture for different imaging applications. Here, we present a systematic comparison of three photodetection mechanisms in silicon–graphene hybrid photodetectors: interfacial photogating, Schottky photodiodes, and Schottky-assisted photogating. These devices have been implemented on the same chip and evaluated under identical conditions. By analyzing responsivity, noise, dynamic range, speed, and array-level imaging, including crosstalk and pixel variation in 5 × 5 arrays, we identify the key performance trade-offs. Interfacial photogating offers high gain and strong low light sensitivity, Schottky-assisted photogating provides higher gain but larger variability and slower response, while Schottky photodiodes enable fast, low-cross-talk imaging. These insights establish practical guidelines for selecting hybrid silicon–graphene detector architectures based on application-specific performance priorities.