In Situ Electron Microscopy Investigation of Physical Properties of Multiwalled Carbon Nanotubes

9971412De Heer多壁碳纳米管的电学和力学性质已经得到了广泛的研究，但仍然知之甚少。在这项研究中，这些问题是通过一系列的原位电子显微镜实验来解决的，在这些实验中，测量了单个、特征良好的纳米管的性质。这些性质包括带电纳米管的电子输运、场发射、静电势和弹性常数。这种测量的可行性已通过一系列初步实验得到证明，这些实验包括：(I)与纳米管有关的电接触的接合和断开；(Ii)原位场发射；(Iii)带电纳米管的相衬效应；以及(Iv)电诱导机械共振的观测。后一种效应暗示了纳米力学的一种新方法。这项研究为处于当代凝聚态物理和材料科学前沿的研究生和博士后研究人员提供了许多培训机会。碳纳米管是近乎完美的石墨管，具有非凡的性能，其中包括非凡的机械强度、高电流载流能力、可能的储氢能力等。为了表征这些性质并发现新的性质，有必要对碳管进行单独研究。首席调查员已经制定了进行此类研究所需的方法。这项研究为在21世纪提供许多就业机会的先进技术领域的研究生和博士后研究助理提供了培训机会。

9971412De HeerElectronic and mechanical properties of multi-walled carbon nanotubes have been widely investigated but are still only poorly understood. In this research these problems are attacked by means of a series of in situ electron microscopy experiments in which the properties of individual, well characterized nanotubes are measured. These properties include the electronic transport, field emission, electrostatic potentials of the electrically charged nanotubes, and elastic constants. The feasibility of such measurements have been demonstrated by a series of preliminary experiments which include (i) the making and breaking of electrical contacts involving nanotubes; (ii) in situ field emission; (iii) phase contrast effects of the charged nanotubes; and (iv) observations of electrically induced mechanical resonances. The latter effect suggests a new approach towards nanomechanics. This research offers many opportunities for the training of graduate students and postdoctoral research associates in a field which stands at the forefront of contemporary condensed matter physics and materials sciences.%%%Carbon nanotubes are nearly perfect graphitic tubes with remarkable properties among which are their exceptional mechanical strength, high current carrying capabilities, possible hydrogen storage capabilities, and others. In order to characterize these properties and to discover new ones it is essential that carbon tubes be studied individually. The principal investigator has developed the required methods for such studies. This research offers opportunities for the training of graduate students and postdoctoral research associates in an advanced technological field that offers many employment opportunities during the 21st Century.***