Atomic Images of Disordered Regions in Graphite Crystals Obtained with Scanning Tunneling Microscope

Using a scanning tunneling microscope (STM), we investigated atomic images of disordered regions in three different grades of graphite crystals in air: (1) single-crystal flake graphite (Kish graphite), (2) highly oriented pyrolytic graphite (HOPG) and (3) pyrolytic graphite (PG). In HOPG and Kish graphites, we found unusual super-structures of graphite crystal located near defects, though almost all the STM images showed defect-free graphite structures. In PG, we could find few regions of graphite structure with STM, though atomic images different from the graphite structure were obtained frequently.