Observation of Au deposited self-assembled monolayers of octanethiol by scanning tunneling microscopy

Ohgi, Taizo; Sheng, Hanyu; Dong, Zhen‐Chao; Nejoh, H.

doi:10.1016/s0039-6028(99)00933-4

Cited by 46 publications

(46 citation statements)

References 19 publications

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“…9 an estimate for the density of alkanethiol molecules on Au{111} is ≃ 4 molecules nm −2 . This value is in agreement with previous reports [37][38][39] and gives an estimate for the molecular occupational density of ≃ 4×10 14 cm −2 , assuming perfect hexagonal arrangement and no defects. Defects that appear as etch pits within the SAM monolayer can be ignored [26,31].…”

Section: Determination Of the Cs Flux Minimum Writing Dosesupporting

confidence: 93%

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

O’Dwyer

Gay

Lesegno

et al. 2005

Journal of Applied Physics

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We report the results of a study into the factors controlling the quality of nanolithographic imaging. Self-assembled monolayer (SAM) coverage, subsequent postetch pattern definition, and minimum feature size all depend on the quality of the Au substrate used in material mask atomic nanolithographic experiments. We find that sputtered Au substrates yield much smoother surfaces and a higher density of {111}-oriented grains than evaporated Au surfaces. Phase imaging with an atomic force microscope shows that the quality and percentage coverage of SAM adsorption are much greater for sputtered Au surfaces. Exposure of the self-assembled monolayer to an optically cooled atomic Cs beam traversing a two-dimensional array of submicron material masks mounted a few microns above the self-assembled monolayer surface allowed determination of the minimum average Cs dose (2 Cs atoms per self-assembled monolayer molecule) to write the monolayer. Suitable wet etching, with etch rates of 2.2 nm min-1, results in optimized pattern definition. Utilizing these optimizations, material mask features as small as 230 nm in diameter with a fractional depth gradient of 0.820 nm were realized

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Section: Determination Of the Cs Flux Minimum Writing Dosesupporting

confidence: 93%

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

O’Dwyer

Gay

Lesegno

et al. 2005

Journal of Applied Physics

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“…[11][12][13][14] Previous studies have shown that vapor-deposited Au or Ag penetrates into the SAM and inserts into the thiol-Au bond at the Au/ SAM interface when it is vacuum-deposited on an alkanethiol SAM with a methyl end group. 2,3,[5][6][7] In contrast, when they are deposited on an alkanedithiol SAM with a thiol end group pointing up, metal nanoparticles are formed on top of the SAM. 1,2,4,8 This is due to the strong interaction between deposited metal nanoparticles and thiol end groups, which reduces the possibility of diffusion of deposited metal nanoparticles into the SAM.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Metal Deposition on Top of an Organic Monolayer

Uosaki

2006

J. Phys. Chem. B

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Electrochemical deposition of metals (platinum or gold) only on top of an organothiolate, 1,4-benzenedimethanethiol (BDMT) or hexanedithiol (HDT), self-assembled monolayer (SAM) on a Au(111) substrate was achieved by electrochemical reduction of PtCl 4 2-or AuCl 4 -ion, which was preadsorbed on one free thiol end group of the dithiol SAM formed on a Au surface, in a metal-ion-free sulfuric acid solution at potentials more negative than the reduction potential of the metal ion. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) measurement after the reduction of preadsorbed PtCl 4 2-ion on BDMT/Au(111) electrode showed the presence of Pt not underneath but on top of the BDMT SAM. After a negative potential scan of the Pt/BDMT/Au(111) electrode to -1.30 V in 0.1 M KOH solution, a typical cyclic voltammogram of a clean Au(111) electrode was obtained, showing that the BDMT SAM with a Pt layer was reductively desorbed. These results proved that a Pt-BDMT SAM-Au substrate sandwich structure without a short circuit between the two metals was successfully constructed by this technique. Furthermore, a decanethiol (DT) monolayer was constructed on a Au layer, which was formed by the reduction of preadsorbed AuCl 4 -ion on HDT/Au(111) electrode. The formation of DT/Au/HDT/Au(111) structure was confirmed as two cathodic peaks corresponding to reductive desorption of DT from Au on top of the HDT/Au(111) at -0.97 V and that of Au/ HDT from Au(111) at -1.12 V were observed when potential was scanned negatively to -1.35 V.

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“…On one hand, atomic steps in the gold substrate play an active role during the self-assembly process, and in one of our recent studies we demonstrated that step edges are feasible sources of defects during selfassembly [13]. The presence of both monatomic high gold islands and vacancy pits has been extensively observed during the self-assembly of a large number of molecules on Au(111) [14][15][16][17]. We recently suggested that one of the roles of vacancy pits is to stabilize the self-assembly, reducing the number of free surface vacancies [13].…”

Section: Introductionmentioning

confidence: 88%

“…Gold adatoms can also be deposited onto a self-assembled monolayer by means of physical vapor deposition. STM experiments have 2 Advances in Chemistry demonstrated that deposited Au atoms penetrate through the self-assembly and preferentially nucleate either at the intersection of different domains or inside domains of less dense striped phase [15,16].…”

Section: Introductionmentioning

confidence: 99%

Density Functional Investigation of the Inclusion of Gold Clusters on a CH₃S Self-Assembled Lattice on Au(111)

Allen

Archibald

Harper³

et al. 2016

Advances in Chemistry

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We employ first-principles density functional theoretical calculations to address the inclusion of gold (Au) clusters in a well-packed CH 3 S self-assembled lattice. We compute CH 3 S adsorption energies to quantify the energetic stability of the self-assembly and gold adsorption and dissolution energies to characterize the structural stability of a series of Au clusters adsorbed at the SAM-Au interface. Our results indicate that the inclusion of Au clusters with less than four Au atoms in the SAM-Au interface enhances the binding of CH 3 S species. In contrast, larger Au clusters destabilize the self-assembly. We attribute this effect to the low-coordinated gold atoms in the cluster. For small clusters, these low-coordinated sites have significantly different electronic properties compared to larger islands, which makes the binding with the self-assembly energetically more favorable. Our results further indicate that Au clusters in the SAM-Au interface are thermodynamically unstable and they will tend to dissolve, producing Au adatoms incorporated in the self-assembly in the form of CH 3 S-Au-SCH 3 species. This is due to the strong S-Au bond which stabilizes single Au adatoms in the self-assembly. Our results provide solid insight into the impact of adatom islands at the CH 3 S-Au interface.

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Observation of Au deposited self-assembled monolayers of octanethiol by scanning tunneling microscopy

Cited by 46 publications

References 19 publications

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

Electrochemical Metal Deposition on Top of an Organic Monolayer

Density Functional Investigation of the Inclusion of Gold Clusters on a CH₃S Self-Assembled Lattice on Au(111)

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Observation of Au deposited self-assembled monolayers of octanethiol by scanning tunneling microscopy

Cited by 46 publications

References 19 publications

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

Electrochemical Metal Deposition on Top of an Organic Monolayer

Density Functional Investigation of the Inclusion of Gold Clusters on a CH3S Self-Assembled Lattice on Au(111)

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Density Functional Investigation of the Inclusion of Gold Clusters on a CH₃S Self-Assembled Lattice on Au(111)