Preparation and Electronic Properties of Nanoporous Carbon Inverse Opal

Carbon inverse opals with three-dimensional nanoporous structures are fabricated by a template method using synthetic opals formed by the sedimentation of SiO 2 spheres. The pore size of the carbon inverse opals ranges widely from approximately 11 nm to 1 µm depending on the diameter of the SiO 2 spheres. The nanostructure size and the degree of graphitization of carbon are also controlled by the change in pyrolysis technique. X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) observations of the carbon inverse opals prepared by pyrolysis at a heat-treatment temperature (HTT) of 2800°C revealed that the graphite layers are formed in the area surrounding the pore and the degree of graphitization depends on the pore size. The electronic properties of the carbon inverse opals are dependent on pore size and the conditions of pyrolysis and are interpreted to be influenced by weak localization effect by taking into consideration the degree of graphitization depending on pore size.