Metallic Adhesion Layer Induced Plasmon Damping and Molecular Linker as a Nondamping Alternative
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- 作者：Terefe G. Habteyes ; Scott Dhuey ; Erin Wood ; Daniel Gargas ; Stefano Cabrini ; P. James Schuck ; A. Paul Alivisatos ; Stephen R. Leone
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：June 26, 2012
- 年：2012
- 卷：6
- 期：6
- 页码：5702-5709
- 全文大小：436K
- 年卷期：v.6,no.6(June 26, 2012)
- ISSN：1936-086X
文摘
Drastic chemical interface plasmon damping is induced by the ultrathin (2 nm) titanium (Ti) adhesion layer; alternatively, molecular adhesion is implemented for lithographic fabrication of plasmonic nanostructures without significant distortion of the plasmonic characteristics. As determined from the homogeneous linewidth of the resonance scattering spectrum of individual gold nanorods, an ultrathin Ti layer reduces the plasmon dephasing time significantly, and it reduces the plasmon scattering amplitude drastically. The increased damping rate and decreased plasmon amplitude are due to the dissipative dielectric function of Ti and the chemical interface plasmon damping where the conduction electrons are transferred across the metal鈥搈etal interface. In addition, a pronounced red shift due to the Ti adhesion layer, more than predicted using electromagnetic simulation, suggests the prevalence of interfacial reactions. By extending the experiment to conductively coupled ring-rod nanostructures, it is shown that a sharp Fano-like resonance feature is smeared out due to the Ti layer. Alternatively, vapor deposition of (3-mercaptopropyl)trimethoxysilane on gently cleaned and activated lithographic patterns functionalizes the glass surface sufficiently to link the gold nanostructures to the surface by sulfur鈥揼old chemical bonds without observable plasmon damping effects.r>