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Hot Electron Harvesting via Photoelectric Ejection and Photothermal Heat Relaxation in Hotspots-Enriched Plasmonic/Photonic Disordered Nanocomposites
ACS Photonics ( IF 7 ) Pub Date : 2017-11-29 00:00:00 , DOI: 10.1021/acsphotonics.7b01156
Long Wen 1 , Yifu Chen 2, 3 , Li Liang 3 , Qin Chen 1
Affiliation  

The ability of plasmonic nanostructures to harvest photons beyond the traditional band-to-band photovoltaic conversion of semiconductors has stimulated intensive research activities in hot electron. As an emerging strategy for energy-harvesting, photodetection and photocatalysis, realization of broadband and efficient plasmonic absorption with easily constructed metal-semconductor (M-S) nanosystems is essential for improving its photoelectric efficiency, while minimizing the cost and complexity of fabrication. Here, we report an approach for near-infrared (NIR) photodetection by combining the randomly and densely packed photonic nanostructures with ultrathin plasmonic coatings. Relying on the Au covered disordered silicon nanoholes (SiNHs) M-S platform, the efficient plasmonic absorption, strong field localization and together with random nature facilitate the broadband photon-energy conversion from both photoelectric hot electron ejection and photothermal hot electron relaxation. Spectral- and time-resolved studies reveal that the proposed Au-SiNHs device is capable of tracking fast-varying NIR signals via hot electron emission process, with a photoresponsivity around 1.5–13 mA/W at wavelengths ranging from 1100 to 1500 nm. With a detailed theoretical analysis based on phenomenological model, different loss mechanisms involved in the hot electron related photoelectric process were described quantitatively and a large improvement potential was identified in the proposed hot electron harvesting platform. In addition, we demonstrated that the closely distributed random voids and tips in the Au-SiNHs structures enable the formation of a substantial amount of hot-spots that can significantly elevate the local temperature through the relaxation of the nonejected hot electrons and, therefore, generate the obvious photothemal mediated photoresponse under voltage driven conditions.

中文翻译:

富集等离子体/光子无序纳米复合材料中通过光电喷射和光热弛豫获得的热电子。

等离子体纳米结构收集光子的能力超出了半导体从传统的带到带光电转换的能力,这刺激了热电子领域的深入研究活动。作为一种新兴的能量收集,光检测和光催化策略,使用易于构建的金属半导体(MS)纳米系统实现宽带和有效的等离子体吸收对于提高其光电效率,同时最大程度地降低制造成本和复杂性至关重要。在这里,我们报告通过结合随机和密集堆积的光子纳米结构与超薄等离子体涂层的近红外(NIR)光电检测方法。依靠Au覆盖的无序硅纳米孔(SiNHs)MS平台,有效的等离子体吸收,强场定位和随机性质共同促进了光电热电子喷射和光热热电子弛豫的宽带光子能量转换。光谱和时间分辨研究表明,拟议的Au-SiNHs器件能够通过热电子发射过程跟踪快速变化的NIR信号,在1100至1500 nm的波长范围内,光响应约为1.5-13 mA / W。通过基于现象学模型的详细理论分析,定量描述了与热电子相关的光电过程中涉及的不同损失机制,并在该热电子采集平台中发现了巨大的改进潜力。此外,
更新日期:2017-11-29
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