High-performance broadband graphene/silicon/graphene photodetectors: From x-ray to near-infrared

Metal–semiconductor–metal (MSM) structures have been widely used and extensively investigated for ultraviolet (UV) detection. However, traditional MSM structures suffer from large dark currents, narrow detection bands, and low collection efficiency. Optimizing these properties for broadband detection in MSM structures is essential for improving the performance and functionality in broader optoelectronics applications. We report a high-performance broadband graphene/thin silicon/graphene photodetector by realizing a synergistic combination of graphene and silicon absorption bandwidths from the x-ray to near-infrared regions. The sensitivity of the proposed photodetector in this spectral range is greatly enhanced. A high responsivity of 0.56 A/W, a high detectivity of 2.72 × 1011 Jones, and a fast response time of 7.2 ns are achieved. Moreover, the real-time array imaging at broadband regions presented in this study can benefit from the independent pixel structures similar to the complementary-metal-oxide-semiconductor (CMOS) architecture. This approach constitutes a reliable route toward a high-performance photodetector with prominent broad-spectrum response, high responsivity, and low noise. These results will motivate strategies to achieve high-performance, broadband image sensors, compatible for on-chip CMOS circuit technology that advances the development of next-generation graphene/silicon image sensors.