Achieving Infrared Detection by All-Si Plasmonic Hot-Electron Detectors with High Detectivity

• Published in: ACS nano Vol. 13; no. 7; pp. 8433 - 8441
• Main Authors: Feng, Bo, Zhu, Jingyuan, Lu, Bingrui, Liu, Feifei, Zhou, Lei, Chen, Yifang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 23.07.2019
• Subjects: all-Si photodetectors; hot electrons; near-infrared detection; plasmonics; perfect absorption
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.9b04236

An improved architecture for all-Si based photoelectronic detectors has been developed, consisting of a specially designed metasurface as the antenna integrated into a Si nanowire array on the insulator by an electron beam lithography based self-alignment process. Simulation using the Finite Difference Time Domain (FDTD) method was carried out to ensure perfect absorption of light by the detector. Optic measurement shows a 90% absorption at 1.05 μm. Photoelectronic characterization demonstrates the responsivity and detectivity as high as 94.5 mA/W and 4.38 × 1011 cm Hz1/2/W, respectively, at 1.15 μm with the bandwidth of 480 nm, which is comparable to that of III–V/II–VI compound detectors. It is understood that the outstanding performances over other reported all-Si based detectors originate from the enhanced quantum efficiency in one-dimensional conduction channels with high density of states, which efficiently accommodate the emitted plasmonic hot electrons for high conduction in the Si nanowires, enabling the near-infrared detection by all-Si based detectors.