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Initial growth process of pentacene molecules on clean Si(001)-2 × 1 substrate was investigated by scanning tunneling microscopy. It is found that the wetting layer, which is not crystalline but disordered, forms before the growth of a first crystalline layer. The wetting layer consists of double layer of the flatly adsorbed pentacene molecules. The formation of the wetting double layer is discussed. The first crystalline layer that is grown on the disordered wetting layer with standing-up pentacene molecules consists of some domains that differ in their crystal structures. Among them, a new pentacene crystal structure is found that can form only on the first layer. In contrast, the second crystalline layer has only single domain. Moreover, we investigated the electronic properties of the pentacene layers by the current–voltage measurements. The pentacene layers are semiconducting with a band gap of about 4 eV.

Growth of a hybrid inorganic–organic layered structure on the Au(111) surface using a one-step solution growth is reported. The hybrid structure is consist of 4,4′-bipyridine [4,4′-BiPyH2]2 + cations, Cl anions and Au adatoms, provided from substrate by means of the adsorbate-induced surface phase transition of a surface reconstruction. Its surface and bulk structures were characterized by scanning tunneling microscopy (STM), secondary ion mass spectrometry (SIMS), and Raman spectroscopy. STM results reveal growth of the first [4,4′-BiPyH2]2 + layer on top of the p 3 × 3 R 30 ° chlorine overlayer formed on the Au(111) surface. These two layers are found to provide a platform for a following three-dimensional growth facilitated by hydrogen bonding, aurophilic and π–π stacking interactions.

The empty-state scanning tunneling microscopy (STM) images of GaAs-c(4 × 4)α show symmetric features at positive biases, contrary to the naive prediction based on electron counting model. In this paper, we report that STM simulations based on first-principles electronic structure calculations successfully demonstrate symmetric images consistent with the STM observations. Furthermore, simple analysis has revealed that the origin of the symmetric images is the combined local electron density of multiple orbitals, and is essentially different from those on GaAs–c(4 × 4)β surfaces.

Cr-adsorbed GaAs ( 0 0 1 ) ‐ c ( 4 × 4 ) α surfaces were investigated in view of a preparatory stage before studying the growth of zincblende CrAs. Cr was adsorbed on a GaAs ( 001 ) ‐ c ( 4 × 4 ) α surface at 200 °C followed by annealing for 2 min. Cr adsorbed surface was investigated with scanning tunneling microscopy at 80 K. Single Cr atom was identified after the classification of Cr dots grown on the surface. The results have suggested that a Cr atom adsorbs on a site between three Ga–As dimers. After further adsorption of Cr, the surface is covered by dots which are higher than a step height of the substrate.

Cu atoms deposited on a zero layer graphene grown on a SiC(0001) substrate, intercalate between the zero layer graphene and the SiC substrate after the thermal annealing above 600 °C, forming a Cu-intercalated single layer graphene. On the Cu-intercalated single layer graphene, a graphene lattice with superstructure due to moire pattern is observed by scanning tunneling microscopy, and specific linear dispersion at the K¯ point as well as a characteristic peak in a C1s core level spectrum, which is originated from a free-standing graphene, is confirmed by photoemission spectroscopy. The Cu-intercalated single layer graphene is found to be n-doped.

An epitaxial silicon-oxide monolayer of chemical composition of Si2O3 (the Si2O3 layer) formed on hexagonal SiC(0001¯) surfaces has been observed by scanning tunneling microscopy (STM). Filled- and empty-state STM images with atomic resolution support the previously reported model. Typical structural defects in the Si2O3 layer are found to be missing SiOn (n = 1, 2, 3) molecules. The band gap of the Si2O3 layer obtained by point tunneling spectroscopy is 5.5±0.5 eV, exhibiting considerable narrowing from that of bulk SiO2, 8.9 eV. It is proposed that the Si2O3 layer is suitable as a relevant interface material for formation of SiC-based metal-oxide-semiconductor devices.

Many studies have observed a clean GaAs(001)-c(4 × 4) surface using scanning tunneling microscopy. These studies have reported the observation of an asymmetric pattern formed from three asymmetric Ga–As dimers. In this study, however, a symmetric pattern was also observed depending on the applied bias voltage. These symmetric (asymmetric) patterns were observed at positive (negative) sample biases.