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Faint ripples were observed at the flat surfaces of 10-monolayer-thick Ag films grown on Si(111)√3×√3-B substrates using scanning tunneling microscopy. The ripples have the 3×3 periodicity and showed no dependence on the bias voltage. The ripples are considered to reflect the Ag(111)1×1 and Si(111)√3×√3-B lattice commensuration at the buried interface, which propagates to the upper layers and causes the geometric corrugation at the Ag film surface. [ABSTRACT FROM AUTHOR]

Abstract: Atomic H chemisorption on the Si(111)√3×√3R30∘-B surface has been studied by thermal desorption spectroscopy (TDS) and scanning tunneling microscopy (STM). The B-modified Si surface is known to be inert towards adsorbates, since the surface dangling bonds of Si adatoms are passivated by B atoms sitting in sub-surface sites. However, it was found that even on a perfectly passivated surface, H is adsorbed on the surface by destroying the original √3×√3 structure. STM observations revealed that H exposure led to the creation of defects at surface sites, and H was subsequently adsorbed as Si-monohydride at these sites. H exposure also caused cluster island formation at the top surface. The islands are composed of hydrogenated amorphous Si atoms or B-hydrogen complexes. [Copyright &y& Elsevier]

Desorption of hydrogen from 6H-SiC(0001) has been systematically studied during graphitization. The surface structure was controlled by thermal desorption of silicon at high temperatures in an ultrahigh vacuum and was characterized by low energy diffraction and Auger electron spectroscopy. The temperature of the dominant peak in the hydrogen desorption spectrum was found to shift from 670 to 490 K between 3×3 and 3×3R30° reconstructions. The shift can be assigned to a change of the adsorption sites from silicon to carbon. [ABSTRACT FROM AUTHOR]