Wakamatsu Satoshi, Fujii Shintaro, Akiba Uichi, Fujihira Masamichi
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.
Ultramicroscopy. 2003 Oct-Nov;97(1-4):19-26. doi: 10.1016/S0304-3991(03)00026-3.
The electrical properties of single phenylene oligomers were studied in terms of the dependence of the tunneling current on the length of the oligomers using self-assembling techniques and scanning tunneling microscopy (STM). It is important to isolate single molecules in an insulating matrix for the measurement of the conductivity of the single molecule. We demonstrate here a novel self-assembled monolayer (SAM) matrix appropriate for isolation of the single molecules. A bicyclo[2.2.2]octane derivative was used for a SAM matrix, in which the single molecules were inserted at molecular lattice defects. The isolated single molecules of phenylene oligomers inserted in the SAM matrix were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights of the molecular protrusions using STM and estimated the decay constant, beta, of the tunneling current through the single phenylene oligomers using a bilayer tunnel junction model.
利用自组装技术和扫描隧道显微镜（STM），通过研究隧穿电流对亚苯基低聚物长度的依赖性，对单亚苯基低聚物的电学性质进行了研究。在绝缘基质中分离单个分子对于测量单分子的电导率很重要。我们在此展示了一种适用于分离单个分子的新型自组装单分子层（SAM）基质。一种双环[2.2.2]辛烷衍生物被用作SAM基质，其中单个分子被插入到分子晶格缺陷处。使用恒流模式，在STM形貌中观察到插入SAM基质中的亚苯基低聚物的单个分离分子呈现为凸起。我们使用STM测量了分子凸起的形貌高度，并使用双层隧道结模型估计了通过单个亚苯基低聚物的隧穿电流的衰减常数β。
