The anomalous RHEED oscillation at the initial stage of homoepitaxial growth on Si (111) 7×7 has been known. We have examined this anomaly, using the growth model for the destruction of the (7 × 7) reconstructed surface and images of scanning tunneling microscopy taken after deposition of Si at 330°C by Köhler et al. We conclude that the anomaly is originated from the two features of the homoepitaxial growth on Si (111) 7×7, that is, formation of many two-dimensional nuclei having two or three bilayer height on large terraces of the starting annealed surface and rapid formation of the nuclei on many domain-boundaries in each layer grown.
Highly oriented pyrolytic graphite treated with NaOH solution was found to form a stage-8 intercalation compound. Superstructures such as 2x2, √3×√3 and noble orthorhombic lattices were observed on the surface, as previously observed on the surfaces of the stage-1 M-GIC (graphite intercalation compound, M=Li, K, Rb, Cs). On the contrary, substrate lattice structure was observed on NaOH-treated MoS2. In addition, new structures near the Fermi level were found to be formed by NaOH-treatment on the surface.