Atomic-scale study of the adsorption of calcium fluoride on Si(100) at low-coverage regime

Abstract

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Two-Dimensional Functionalized Ultrathin Semi-Insulating CaF2 Layer on the Si(100) Surface at a Low Temperature for Molecular Electronic Decoupling

“…the silicon dimer rows. Note that the stripes are surrounded by either residual bare silicon dimer rows or spots of WL 29 . The averaged distance between each stripe is 11.7 ± 0.3 Å.…”

“…1b. Inside these patches, each unit-cell is oriented along the silicon dimer rows [110] direction and their relative direction can be identical or head-to-tail 29 . Increasing the amount of CaF2 molecules during surface exposition results in observing the second step of the VW process leading to the formation of ultra-thin ribbons of stripes, as it can be observed in Fig.…”

“…From this, we can locate the relative positions of the oriented WL unit-cells in the area of the ribbon of stripes, as if they were part of this structure. The direction of the WL unitcell is here chosen via a careful comparison of the surrounding of the ribbon of stripes 29 . This assumption reveals how the substitutional Ca atoms of the WL can be aligned along the stripes (light green balls of the cells).…”

“…At smaller scale, the epitaxial growth of CaF2 on Si(100) surfaces exhibits ultrathin insulating anisotropic reconstructions forming ribbons of stripes that offer additional functionalities for organizing adsorbates 27 . While the electronic structure of the CaF2/Si(100) has been investigated with mesoscopic techniques 28 , it is of crucial importance for the understanding of their electronic structure to investigate their atomic scale formation 29 . Yet, a detailed and complete description of the precise atomic and electronic structure of ultrathin CaF2 insulating ribbons of stripes on Si(100) is lacking, as well as the characterization of the interaction of this type of semi-insulating layer with molecular adsorbates.…”

Atomic-scale control of hydrogen bonding on a bare Si(100)-2×1 surface

“…1(a)]. 24 The STM tip is then located at a given position [the red dot in Fig. 1(a)], and the surface voltage is switched from the scanning conditions at a negative bias (V s = −1.4 V) to a positive bias V s = +1.4 V. During this excitation procedure, the feedback loop of the STM is switched off, and the tunnel current is recorded, whereby, the height of the STM tip is kept constant.…”