Measuring relative barrier heights in molecular electronic junctions with transition voltage spectroscopy
Measuring relative barrier heights in molecular electronic junctions with transition voltage spectroscopy
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DOI：
10.1021/nn700424u
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发表时间：
2008-05-01
期刊：
影响因子：
17.1
通讯作者：
Kushmerick, James G.
中科院分区：
文献类型：
--
作者：
Beebe, Jeremy M.;Kim, BongSoo;Kushmerick, James G.
虽然分子器件表现出潜在的有用的电行为已被证明，影响分子电子结中的电荷输运的因素的深入理解尚未完全实现。最近的工作表明，在分子电子器件中发生了从直接隧穿到场致发射的机制转变。实现这种转变所需的电压大小是分子特异性的，因此转变电压的测量构成了光谱学的一种形式。在这里，我们确定了一系列的烷硫醇分子的过渡电压是不变的分子长度，而共轭分子的过渡电压直接取决于共轭途径已被延长的方式。最后，通过检查作为接触金属的函数的过渡电压，我们表明，这种技术可以用来确定一个给定的分子结的主导电荷载流子。
Though molecular devices exhibiting potentially useful electrical behavior have been demonstrated, a deep understanding of the factors that influence charge transport in molecular electronic junctions has yet to be fully realized. Recent work has shown that a mechanistic transition occurs from direct tunneling to field emission in molecular electronic devices. The magnitude of the voltage required to enact this transition is molecule-specific, and thus measurement of the transition voltage constitutes a form of spectroscopy. Here we determine that the transition voltage for a series of alkanethiol molecules is invariant with molecular length, while the transition voltage of a conjugated molecule depends directly on the manner in which the conjugation pathway has been extended. Finally, by examining the transition voltage as a function of contact metal, we show that this technique can be used to determine the dominant charge carrier for a given molecular junction.