Confinement-Enhanced Core–Shell Avalanche Photodetectors

作者：Zongwen Li, Yunfei Xie, Zishun Li, Q. X. Zhang, Qianqian Zhang, Yuexing Xia, Chuan Qin, Zhixiang Zhang, Tian Feng, Yuan Ma, Jian Chai, Muhammad Abid Anwar, Muhammad Faizan Malik, Yitao Ma, Yuda Zhao, Yaping Dan, Srikrishna Chanakya Bodepudi, Xinfeng Liu, Xiaorui Zheng, Huan Hu, Bin Yu, Yang Xu · 发表于：ACS Nano · 年份：2025 · DOI：10.1021/acsnano.5c06288 · 被引用次数：7 · 研究领域：Photonic and Optical Devices、Advanced Optical Sensing Technologies、Nanowire Synthesis and Applications

Silicon-based avalanche photodetectors (Si-APDs) are promising candidates for complementary metal oxide semiconductor (CMOS)-compatible optoelectronic systems, leveraging their inherent multiplication mechanism to compensate for silicon’s weak absorption at the near-infrared (NIR) range through advanced structural engineering. However, conventional free-space Si-APDs suffer from inevitable limitations, most notably spatially nonuniform avalanche triggering arising from stochastic carrier injection, excessive multiplication noise caused by unregulated avalanche paths, and surface recombination losses at heterojunction interfaces, which collectively constrain their development in emerging NIR detection. Herein, we construct and demonstrate a novel SiO 2 -passivated Si nanowire (SiO 2 -SiNW)/graphene confinement-enhanced photodetector, where vertical SiO 2 -SiNWs function as a core–shell nanoresonator system. The proposed design structure leverages photon confinement to enhance light absorption at 1550 nm, while the localized field enhancement at the SiNW/graphene vertical van der Waals (vdW) interface facilitates avalanche photodetection. Through advanced structural engineering, the device exhibits a responsivity of 56.58 A/W and a high avalanche gain of 2.64 × 10 4, attributed to the synergistic interplay of nanoresonator-enhanced light–matter interaction and efficient carrier multiplication within the confined avalanche regime. The strategic integration of dielectric-engineer...