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The scanning tunneling microscopy (STM) and high-resolution core-level photoemission spectroscopy (HRCLPES) are used for elucidating the adsorption and electronic structures of Al[Cl.sub.3] on Ge(100). The studies have shown that Al[Cl.sub.3] molecules adsorb on the Ge(100) surface via a cycloaddition-like reaction and form di-[sigma] bonds in which the Al[Cl.sub.3] molecules have interacted with the surface dimers of Ge(100).

The adsorption geometry of cis-2-butene-1,4-diol (BEDO, HOCH2CHCHCH2OH) on Si(100)-2× 1 was studied using scanning tunneling microscopy (STM), high resolution X-ray photoemission spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Bias-voltage-dependent STM images exhibited features characteristic of two distinct BEDO adsorption geometries. One feature was a bright protrusion located on the center of a single dimer, indicating an on-top configuration. The low bias-voltage STM image clearly showed dark features indicative of the formation of Si−H bonds on adjacent dimers in the same dimer row. The other feature was a bright protrusion bridged on end between two adjacent dimers in the same dimer row, indicating an end-bridge configuration. Accompanying this feature, two dark features attributed to Si−H bonds were observed on opposite positions to the bridged protrusion. From the XPS results, the Si 2pcore level spectra revealed that the dimer atoms are involved in the formation of Si−O and Si−H bonds. On the other hand, carbon K-edge NEXAFS spectra showed that the CC bond does not participate in the adsorption reaction and remains as an unreacted group. Collectively, the experimental results indicate that the adsorption of BEDO on Si(100)-2× 1 occurs through the formation of two Si−O bonds via nucleophilic reaction between the two OH groups of BEDO and two Si−Si dimers. Importantly, the maintenance of the CC bond means that the CC functional group can be utilized as a new reaction site for further surface chemical reactions. [ABSTRACT FROM AUTHOR]

The article reports on the molecular adsorption of Lewis base molecules with a lone pair of electrons on Ge(100). The high-resolution core-level photoemission spectroscopy (HRCLPES) was used to clarify the electronic structure of aluminum trichloride (AlCl3), which is a lewis acid, adsorbed on Ge(100). On the other hand, the study of the adsorption of Lewis acid molecules will improve the understanding of how to selectively construct and design self-assembled nanostructure.