Bonding and Structure of 1,4-Cyclohexadiene Chemisorbed on Si(100)(2×1)

Hamaguchi, Kanae; Machida, Shuichi; Nagao, Masashi; Yasui, Fumiko; Mukai, Kozo; Yamashita, Yoshiyuki; Yoshinobu, Jun; Kato, Hiroyuki; Okuyama, Hiroshi; Kawai, Maki; Sato, Tomoshige; Iwatsuki, Masashi

doi:10.1021/jp0029358

Cited by 41 publications

(65 citation statements)

References 42 publications

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“…41 Another change is the appearance of a new peak at ϳ510 cm Ϫ1 , ascribed to Si-C stretching mode. 42 Furthermore, the characteristic vibrational modes ͓͑C-C͔͒ of monosubstituted phenyl ring around 1580-1650 cm Ϫ1 ,…”

Section: Resultsmentioning

confidence: 99%

Adsorption of phenylacetylene on Si(100)-2×1: Reaction mechanism and formation of a styrene-like π-conjugation system

Tao

Qiao

et al. 2003

Phys. Rev. B

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The interactions of phentylacetylene and phenylacetylene-␣-d 1 with Si(100)-2ϫ1 have been studied as a model system to mechanistically understand the adsorption of conjugated -electron aromatic substitutions on Si(100)-2ϫ1. Vibrational signatures show that phenylacetylene covalently binds to the surface through a ͓2 ϩ2͔-like cycloaddition pathway between the external CwC and SivSi dimer, forming styrene-like conjugation structure which was further supported by the chemical-shift of C 1s core level. These experimental results are consistent with the density-functional theory ͓B3LYP/6-311//ϩG͑d͔͒ calculations. The resulting styrenelike conjugation structures may possibly be employed as an intermediate for further organic syntheses and fabrication of molecular architecture for modification and functionalization of Si surfaces, or as a monomer for polymerization on Si surfaces.

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Section: Resultsmentioning

confidence: 99%

Adsorption of phenylacetylene on Si(100)-2×1: Reaction mechanism and formation of a styrene-like π-conjugation system

Tao

Qiao

et al. 2003

Phys. Rev. B

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“…This polarizationtype behavior suggested that the mode could be a Si-C surface motion oriented perpendicular to the Si(111) surface plane, although this peak position would be higher in energy than most proposed Si-C stretches on alkylated Si(111) surfaces observed previously with HREELS. [28][29][30][31][32][33] Finally, Figure 3 shows a broad feature at ∼620 cm -1 at both data collection angles. This mode corresponded to a Si-Si lattice phonon mode that was not perfectly subtracted from the CH 3 -terminated surface by referencing with the Cl-terminated surface.…”

Section: Tirs Peak Area (Cmmentioning

confidence: 99%

Transmission Infrared Spectroscopy of Methyl- and Ethyl-Terminated Silicon(111) Surfaces

et al. 2006

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Transmission infrared spectroscopy (TIRS) has been used to investigate the surface-bound species formed in the two-step chlorination/alkylation reaction of crystalline (111)-oriented Si surfaces. Spectra were obtained after hydrogen termination, chlorine termination, and reaction of the Cl-Si(111) surface with CH 3 MgX or C 2 H 5 MgX (X ) Cl, Br) to form methyl (CH 3 )-or ethyl (C 2 H 5 )-terminated Si(111) surfaces, respectively. Freshly etched H-terminated Si(111) surfaces that were subsequently chlorinated by immersion in a saturated solution of PCl 5 in chlorobenzene were characterized by complete loss of the Si-H stretching and bending modes at 2083 and 627 cm -1 , respectively, and the appearance of Si-Cl modes at 583 and 528 cm -1 . TIRS of the CH 3 -terminated Si(111) surface exhibited a peak at 1257 cm -1 polarized perpendicular to the surface assigned to the C-H symmetrical bending, or "umbrella" motion, of the methyl group. A peak observed at 757 cm -1 polarized parallel to the surface was assigned to the C-H rocking motion. Alkyl C-H stretch modes on both the CH 3 -and C 2 H 5 -terminated surfaces were observed near 2900 cm -1 . The C 2 H 5 -terminated Si(111) surface additionally exhibited broad bands at 2068 and 2080 cm -1 , respectively, polarized perpendicular to the surface, as well as peaks at 620 and 627 cm -1 , respectively, polarized parallel to the surface. These modes were assigned to the Si-H stretching and bending motions, respectively, resulting from H-termination of surface atoms that did not form Si-C bonds during the ethylation reaction. I. IntroductionAlkylation of silicon(111) surfaces has attracted significant recent attention due to the potential for obtaining molecular level control over the electrical, electrochemical, and chemical properties of Si surfaces. 1-5 Hydrogen-terminated Si(111) surfaces have a very low surface electron-hole recombination velocity, 6 but oxidize rapidly in ambient air, forming a large number of surface electronic trap states. 2 In contrast, alkylated Si surfaces prepared through a two-step chlorination/alkylation procedure show excellent chemical stability and low surface charge carrier recombination rates for extended time periods, even as they are exposed to ambient air. 1,2 Methyl moieties are the only saturated hydrocarbon group which can sterically form a Si-C bond to every atop site on an unreconstructed Si(111) surface, because van der Waals interactions between neighboring methylene units should prevent C 2 H 5 -and other alkyls from terminating every Si atop site. 7 Furthermore, the sp 3 -hybridized Si-C bond on the Si(111) surface should orient the methyl groups on the CH 3 -terminated surfaces normal to the surface plane, as shown in Chart 1. This orientation should produce diagnostic signatures and polarizations in the vibrational spectrum of such surfaces. Recent scanning tunneling microscopy 8 and low-energy electron diffraction studies 9 have revealed both short-range and long-range order on CH 3 -terminated Si surfaces. However, at pr...

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“…Another solid evidence for the direct interaction of (sp 2 )C atoms with Si surface dangling bonds is the appearance of a vibrational feature at 651 cm Ϫ1 assigned to SiuC stretching mode. 22 Moreover, the absence of the (SiuH) intensity at ϳ2000-2100 cm Ϫ1 in the present case readily excludes the formation of the -bonded species involving CuH bond scission and SiuH bond formation. 23 A schematic presentation of ͓4ϩ2͔-and ͓2ϩ2͔-like cycloaddtion reactions is shown in Fig.…”

Section: Resultsmentioning

confidence: 46%

Multiple configurations ofN-methylpyrrole binding onSi(111)−7×7

et al. 2003

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The adsorption configurations of N-methylpyrrole on Si(111)-7ϫ7 were investigated using high-resolution electron energy-loss spectroscopy, x-ray photoelectron spectroscopy ͑XPS͒, scanning tunneling microscopy ͑STM͒, and density function theory calculations. Compared to physisorbed N-methylpyrrole, chemisorbed molecules present a different vibrational feature at 2886 cm Ϫ1 attributable to ͓(Si)C sp3 -H͔ in addition to the vibrational features of (sp͒, and CuH of CH 3 ͑2944 cm Ϫ1 ͒ stretching modes, demonstrating the direct interaction between CvC bonds and Si(111)-7ϫ7. The major change of N 1s XPS spectrum of N-methylpyrrole upon chemisorption strongly suggests the coexistence of two chemisorption states, further confirmed in the strong dependence of STM image features on the sample bias together with statistical analysis. The concurrent occurrence of ͓4ϩ2͔ and ͓2ϩ2͔ cycloadditions is proposed to account for these two adsorption configurations of N-methylpyrrole on Si(111)-7ϫ7.

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Bonding and Structure of 1,4-Cyclohexadiene Chemisorbed on Si(100)(2×1)

Cited by 41 publications

References 42 publications

Adsorption of phenylacetylene on Si(100)-2×1: Reaction mechanism and formation of a styrene-like π-conjugation system

Adsorption of phenylacetylene on Si(100)-2×1: Reaction mechanism and formation of a styrene-like π-conjugation system

Transmission Infrared Spectroscopy of Methyl- and Ethyl-Terminated Silicon(111) Surfaces

Multiple configurations ofN-methylpyrrole binding onSi(111)−7×7

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