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Wafer‐Scale Double‐Layer Stacked Au/Al 2 O 3 @Au Nanosphere Structure with Tunable Nanospacing for Surface‐Enhanced Raman Scattering
Author(s) -
Hu Zhaosheng,
Liu Zhe,
Li Lin,
Quan Baogang,
Li Yunlong,
Li Junjie,
Gu Changzhi
Publication year - 2014
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201400509
Subject(s) - materials science , plasmon , raman scattering , nanosphere lithography , nanostructure , wafer , nanotechnology , optoelectronics , atomic layer deposition , substrate (aquarium) , raman spectroscopy , layer (electronics) , nanophotonics , fabrication , optics , medicine , oceanography , physics , alternative medicine , pathology , geology
Fabricating perfect plasmonic nanostructures has been a major challenge in surface enhanced Raman scattering (SERS) research. Here, a double‐layer stacked Au/Al 2 O 3 @Au nanosphere structures is designed on the silicon wafer to bring high density, high intensity “hot spots” effect. A simply reproducible high‐throughput approach is shown to fabricate feasibly this plasmonic nanostructures by rapid thermal annealing (RTA) and atomic layer deposition process (ALD). The double‐layer stacked Au nanospheres construct a three‐dimensional plasmonic nanostructure with tunable nanospacing and high‐density nanojunctions between adjacent Au nanospheres by ultrathin Al 2 O 3 isolation layer, producing highly strong plasmonic coupling so that the electromagnetic near‐field is greatly enhanced to obtain a highly uniform increase of SERS with an enhancement factor (EF) of over 10 7 . Both heterogeneous nanosphere group (Au/Al 2 O 3 @Ag) and pyramid‐shaped arrays structure substrate can help to increase the SERS signals further, with a EF of nearly 10 9 . These wafer‐scale, high density homo/hetero‐metal‐nanosphere arrays with tunable nanojunction between adjacent shell‐isolated nanospheres have significant implications for ultrasensitive Raman detection, molecular electronics, and nanophotonics.