2006 年 48 巻 2 号 p. 127-132
A new method to analyze the thickness of a very thin film without any substrates, which is called here“nanofilm”, has been developed. When it is composed of the stacking of more than about 10 atomic layers, the thickness can easily be determined by counting the number of lattice fringes, appearing in high-resolution transmission electron microscope (HRTEM) images of its cross section, which arise at puckered sites. For further thinner films, however, this is not the case, since they are so flexible that the diffraction condition quickly varies depending on sites and HRTEM images do not necessarily reflect the exact number of stack-ing layers. The flexibility is closely related to the thickness. This means that the thickness can be determined by the quantitative analysis of electron diffraction intensity, which takes an apparent temperature factor into account. We have applied this method to a carbon nanofllm (CNF) and succeeded in clarifying the number of stacking layers unambiguously. It has been proved that a single sheet of graphene, which is a carbon hexagonal-ring plane, exists in a CNF as one of component films.