Conductance and SERS Measurement of Benzenedithiol Molecules Bridging Between Au Electrodes

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• 作者：Ryuji Matsuhita ; Masyo Horikawa ; Yasuhisa Naitoh ; Hisao Nakamura ; Manabu Kiguchi
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：January 31, 2013
• 年：2013
• 卷：117
• 期：4
• 页码：1791-1795
• 全文大小：265K
• 年卷期：v.117,no.4(January 31, 2013)
• ISSN：1932-7455

文摘

We have measured electric conductance and surface enhanced Raman scattering (SERS) spectra for the benzenedithiol molecules bridging between Au nano gap electrodes at room temperature to investigate the electric and optical properties of the molecular junction. The current鈥搗oltage characteristic of the molecular junction was investigated based on the single level tunneling model considering that the Fermi distribution function got smeared out for finite temperature, which provided the information on the number of molecules bridging metal electrodes, energy difference between conduction orbital and Fermi level, strength of the molecule-metal coupling. The conductance measurements confirmed the interaction between molecule and Au electrodes. Due to the interaction between molecule and metal electrodes, we could observe the SERS spectra characteristic of the molecular junction. The SERS measurement showed the disappearance of the SH modes and red shift of some internal vibration modes, which confirmed the molecular bridge between Au electrodes. For some molecular junctions, we observed the b₂ mode, which was not observed in the bulk crystal. The appearance of the b₂ mode could be explained by the photon-driven charge transfer from molecule to metal electrodes.