Year: 2020
Type: preprint
Abstract: Graphene with linear energy dispersion and weak electron-phonon interaction is highly anticipated to harvest hot-electrons in a broad wavelength range from ultraviolet to terahertz. However, the limited absorption (~2.3%) and serious backscattering of hot-electrons associated with single-layer graphene result in inadequate quantum yields, impeding their practically broadband photodetection, especially in the mid-infrared range. Here, we report a macroscopic assembled graphene (MAG)/silicon heterojunction for ultrafast mid-infrared photodetection. The highly crystalline 2-inch scale MAG with tunable thickness from 10 to 60 nm is produced by scalable wet-assembly of commercial graphene oxide followed by thermal annealing. The MAG/Si Schottky diode exhibits broadband photodetection capability in 1-10 μm at room temperature with fast response (120-130 ns, 4 mm2 window) and high detectivity (1011 to 106 Jones), outperforming single-layer graphene/Si photodetectors by 2 to 8 orders in transient photocurrent. This optoelectronic performance is attributed to the superior advantages of MAG (~40% of light absorption, ~23 ps of carrier relaxation time, and high quasi-equilibrated hot-carrier-multiplication gain), atomic-scale contact interface of MAG and silicon, and impact-ionization avalanche gain (~100 times) from silicon. The MAG provides a long-range platform to understand the hot-carrier dynamics in stacked 2D materials, leading to next-generation broadband silicon-based image sensors.
Source: Research Square
Authors: Chao Gao, Li Peng, Sichao Du, Lixiang Liu, Srikrishna Bodepudi, Lingfei Li, Wei Liu, Xin Cong, Runchen Lai, Wenzhang Fang, Xiaoxue Cao, Xinyu Liu, Muhammad Abid, Jianhang Lv, Junxue Liu, Shengye Jin, Kaifeng Wu, Qiaohui Zhou, Haiming Zhu, Miao-Ling Lin, Ping-Heng Tan, Qihua Xiong, Xiaomu Wang, Weida Hu, Xiangfeng Duan, Bin Yu, Wenyan Yin, Zhen Xu, Yang Xu
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3109689740