Single naphthalene and anthracene molecular junctions using Ag and Cu electrodes in ultra high vacuum
Single naphthalene and anthracene molecular junctions using Ag and Cu electrodes in ultra high vacuum
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DOI：
10.1016/j.apsusc.2015.05.071
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发表时间：
2015-11
影响因子：
6.7
通讯作者：
S. Fujii;S. Kaneko;L. Chenyang;M. Kiguchi
中科院分区：
文献类型：
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作者：
S. Fujii;S. Kaneko;L. Chenyang;M. Kiguchi
在超高真空条件下，利用机械可控断结技术，研究了连接在Ag和Cu电极上的单萘和蒽分子结的电荷输运。我们特别关注了金属-π相互作用对分子结形成概率的影响。我们发现，在0.2G0（G0= 2e2/h）下，烯类分子（如萘和蒽）的单分子连接点表现出高导电性。分子结的形成概率为ca。Ag体系20%，Cu体系>40%。相对于苯/金结，分子结的高形成概率可以定性地解释为尺寸效应，其中较大的萘和蒽分子比小分子如苯更能有效地弥合金属电极之间的间隙。acene/Cu结的形成概率高于acene/Ag结。这一结果表明，要定量评价Ag和Cu体系分子结的形成概率，不仅要考虑尺寸效应，还要考虑金属-π相互作用的程度。
We present a charge transport study on single naphthalene and anthracene molecular junctions wired into Ag and Cu electrodes using mechanically controllable break junction technique at 100 K under ultra-high vacuum condition. In particular we focus on effect of metal–π interaction on the formation probability of the molecular junctions. We found that the single molecular junctions of the acene molecules (e.g.naphthalene and anthracene) exhibit highly conductive character below 0.2G0(G0= 2e2/h). The acene molecular junctions displayed formation probability ofca.20% for Ag system and >40% for Cu system. The high formation probability of the molecular junctions with respect to benzene/Au junctions can be qualitatively explained by size effect, in which larger molecules of the naphthalene and anthracene can effectively bridge the gap between metal electrodes compared with small molecule such as benzene. The acene/Cu junctions displayed higher formation probability than the acene/Ag junctions. This result demonstrated that not only the size effect but the degree of the metal–π interaction have to be taken into account to quantitatively evaluate the formation probability of the molecular junctions for Ag and Cu system.