Enhanced Graphene Photodetector with Fractal Metasurface

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• 作者：Jieran FangDi Wang ; Clayton T. DeVaultTing-Fung Chung ; Yong P. Chen ; Alexandra Boltasseva ; Vladimir M. Shalaev ; Alexander V. Kildishev
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：17
• 期：1
• 页码：57-62
• 全文大小：409K
• ISSN：1530-6992

文摘

Graphene has been demonstrated to be a promising photodetection material because of its ultrabroadband optical absorption, compatibility with CMOS technology, and dynamic tunability in optical and electrical properties. However, being a single atomic layer thick, graphene has intrinsically small optical absorption, which hinders its incorporation with modern photodetecting systems. In this work, we propose a gold snowflake-like fractal metasurface design to realize broadband and polarization-insensitive plasmonic enhancement in graphene photodetector. We experimentally obtain an enhanced photovoltage from the fractal metasurface that is an order of magnitude greater than that generated at a plain gold–graphene edge and such an enhancement in the photovoltage sustains over the entire visible spectrum. We also observed a relatively constant photoresponse with respect to polarization angles of incident light, as a result of the combination of two orthogonally oriented concentric hexagonal fractal geometries in one metasurface.