A novel growth mode of alkane films on a SiO2 surface

Mo, H. J.; Taub, H.; Volkmann, U.G.; Pino, Manuel del; Ehrlich, Steven N.; Hansen, Flemming Yssing; E, Lu; Miceli, P. F.

doi:10.1016/s0009-2614(03)01106-0

Cited by 43 publications

(89 citation statements)

References 18 publications

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“…In these cases (not shown here), we observed Bragg peaks from preferentially oriented bulk particles consistent with the nucleation of an orthorhombic phase as found for C32 deposited onto the SiO 2 -coated Si(100) substrates [6].…”

Section: Resultssupporting

confidence: 84%

“…Also, for both substrates at sufficiently high coverage, preferentially oriented bulk particles coexist with the film, as in Stranski-Krastanov growth. On the SiO 2 surface, two series of bulk Bragg peaks are observed, corresponding to particles of a surface stabilized orthorhombic phase as well as the previously reported monoclinic structure [7], both oriented with the ab-plane parallel to the film plane, as shown schematically in figure 3 [6].…”

Section: Discussionsupporting

confidence: 64%

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Studies of the structure and growth mode of dotriacontane films by synchrotron x-ray scattering and molecular dynamics simulations

Trogisch

Taub

et al. 2004

J. Phys.: Condens. Matter

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We report on synchrotron x-ray scattering experiments and molecular dynamics simulations of the structure and growth mode of dotriacontane (n-C 32 H 66 or C32) films adsorbed on Ag(111) and SiO 2 -coated Si(100) substrates. On the SiO 2 surface, the x-ray measurements confirm a structural model of the solid film inferred from high-resolution ellipsometry measurements in which one or two layers of C32 adsorb with the long axis of the molecule oriented parallel to the interface followed by a monolayer in which the molecules have a perpendicular orientation. At higher C32 coverages, preferentially oriented bulk particles nucleate, consistent with a Stranski-Krastanov growth mode. On the Ag(111) surface, we again observe one or two layers of the 'parallel' film but no evidence of the perpendicular monolayer before nucleation of the preferentially oriented bulk particles. We compare the experimentally observed structures with molecular dynamics simulations of a multilayer film of the homologous C24 molecule.

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Section: Resultssupporting

confidence: 84%

Section: Discussionsupporting

confidence: 64%

Studies of the structure and growth mode of dotriacontane films by synchrotron x-ray scattering and molecular dynamics simulations

Trogisch

Taub

et al. 2004

J. Phys.: Condens. Matter

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“…Nanoscale observation of delayering in alkane films X-ray diffraction [11] and contact mode AFM [12] measurements indicate that these particles have an orthorhombic structure in which the C32 molecules are aligned perpendicular to the SiO 2 surface. Because these mesa-shaped orthorhombic particles appear on annealing and retain their structure on cooling to room temperature as well as in a subsequent heating cycle, we believe they represent the equilibrium structure at room temperature.…”

Section: -P2mentioning

confidence: 99%

Nanoscale observation of delayering in alkane films

et al. 2007

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-Tapping-mode Atomic Force Microscopy and synchrotron X-ray scattering measurements on dotriacontane (n-C32H66 or C32) films adsorbed on SiO2-coated Si(100) wafers reveal a narrow temperature range near the bulk C32 melting point T b in which a monolayer phase of C32 molecules oriented perpendicular to surface is stable. This monolayer phase undergoes a delayering transition to a three-dimensional (3D) fluid phase on heating to just above T b and to a solid 3D phase on cooling below T b . An equilibrium phase diagram provides a useful framework for interpreting the unusual spreading and receding of the monolayer observed in transitions to and from the respective 3D phases.

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“…3,24,25 Of these systems, probably the best characterized are monolayers of C32 and C24 on high-quality graphite basal-plane surfaces that have been investigated by scanning tunneling microscopy ͑STM͒, [10][11][12][13][14] x-ray diffraction, 15 and neutron scattering. [16][17][18][19][20][21] Graphite substrates also have the advantage that relatively reliable empirical atom-atom potentials are available for representing the molecule/graphite basal-plane interaction.…”

Section: Introductionmentioning

confidence: 99%

Structure and phase transitions of monolayers of intermediate-length n-alkanes on graphite studied by neutron diffraction and molecular dynamics simulation

Diama

Matthies

Herwig

et al. 2009

The Journal of Chemical Physics

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We present evidence from neutron diffraction measurements and molecular dynamics ͑MD͒ simulations of three different monolayer phases of the intermediate-length alkanes tetracosane ͑n-C 24 H 50 denoted as C24͒ and dotriacontane ͑n-C 32 H 66 denoted as C32͒ adsorbed on a graphite basal-plane surface. Our measurements indicate that the two monolayer films differ principally in the transition temperatures between phases. At the lowest temperatures, both C24 and C32 form a crystalline monolayer phase with a rectangular-centered ͑RC͒ structure. The two sublattices of the RC structure each consists of parallel rows of molecules in their all-trans conformation aligned with their long axis parallel to the surface and forming so-called lamellas of width approximately equal to the all-trans length of the molecule. The RC structure is uniaxially commensurate with the graphite surface in its ͓110͔ direction such that the distance between molecular rows in a lamella is 4.26 Å = ͱ 3a g , where a g = 2.46 Å is the lattice constant of the graphite basal plane. Molecules in adjacent rows of a lamella alternate in orientation between the carbon skeletal plane being parallel and perpendicular to the graphite surface. Upon heating, the crystalline monolayers transform to a "smectic" phase in which the inter-row spacing within a lamella expands by ϳ10% and the molecules are predominantly oriented with the carbon skeletal plane parallel to the graphite surface. In the smectic phase, the MD simulations show evidence of broadening of the lamella boundaries as a result of molecules diffusing parallel to their long axis. At still higher temperatures, they indicate that the introduction of gauche defects into the alkane chains drives a melting transition to a monolayer fluid phase as reported previously.

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A novel growth mode of alkane films on a SiO2 surface

Cited by 43 publications

References 18 publications

Studies of the structure and growth mode of dotriacontane films by synchrotron x-ray scattering and molecular dynamics simulations

Studies of the structure and growth mode of dotriacontane films by synchrotron x-ray scattering and molecular dynamics simulations

Nanoscale observation of delayering in alkane films

Structure and phase transitions of monolayers of intermediate-length n-alkanes on graphite studied by neutron diffraction and molecular dynamics simulation

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