Graphene/silicon infrared photoelectric detection based on black phosphorus modification

In recent years, graphene/silicon heterojunction photodetectors have attracted wide attention in the world, and promoted the research and development of related devices. However, the ultra-low light absorption of graphene, coupled with the limitation of the silicon band gap, result in a constrained absorption capacity for infrared light within this category of photodetectors. Although the device performance can be improved by introducing some optical structures such as surface plasmons, optical waveguides, optical microcavities, quantum dots, the preparation process is complex, resulting in high cost and low yield. In this paper, we propose a novel infrared photodetector structure based on graphene/silicon ternary heterojunction modified with black phosphorus. Black phosphorus is used to absorb near-infrared light, generate photogenerated charge carriers, which then injected into graphene to change the Fermi level of graphene, thus changing the Schottky barrier between graphene and silicon, so that the carriers are easier to cross the Schottky barrier and be collected by silicon to generate photocurrent and realize near-infrared photoelectric detection. The experimental results show that compared with the graphene/silicon photodetectors without black phosphorus, in the wavelength range from 1500 nm to 1800 nm, the device responsiveness exceeds 0.1 mA/W, and reaches a maximum value of 0.18 mA/W at 1730 nm.