Mechanism of Formation of Au Vacancy Islands in Alkanethiol Monolayers on Au(111)

Poirier, G. E.

doi:10.1021/la960777z

Cited by 327 publications

(394 citation statements)

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“…Results presented here for sputtered Au on Cr show remarkable similarity to the 'etch pits' observed in Refs. [19,32] At this point it is instructive to outline the detail of conformational isomers which describe the structure of the alkanethiol molecular chain. In acyclical structures, such as 1-nonanethiol, rotation about a single bond can produce an infinite number of arrangements.…”

Section: Resultsmentioning

confidence: 99%

“…The structure of the alkanethiols was not examined in detail, nor was the effect of higher grain boundary densities on the molecular package arrangement of the SAM on the surface. The long range order of alkanethiol self assembly was addressed in early STM studies [19][20][21][22][23][24][25] revealing that alkanethiol monolayers on Au{111}, in particular, exhibit a distribution of pit-like defects which are known not to exist on the Au surface. Although initially believed that the pits arose from missing or loosely packed alkanethiols [20][21][22], later studies revealed that they were in fact two-dimensional islands of Au vacancies [26] consistent with the Au{111} single-atom step height of 0.24 nm.…”

Section: Introductionmentioning

confidence: 99%

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The Nature of Alkanethiol Self-Assembled Monolayer Adsorption on Sputtered Gold Substrates

2004

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A detailed study of the self-assembly and coverage by 1-nonanethiol of sputtered Au surfaces using molecular resolution atomic force microscopy (AFM) and scanning tunneling microscopy (STM) is presented. The monolayer self-assembles on a smooth Au surface composed predominantly of {111} oriented grains. The domains of the alkanethiol monolayer are observed with sizes typically of 5−25 nm, and multiple molecular domains can exist within one Au grain. STM imaging shows that the (4 × 2) superlattice structure is observed as a (3 × 2 ) structure when imaged under noncontact AFM conditions. The 1-nonanethiol molecules reside in the threefold hollow sites of the Au{111} lattice and aligned along its [112] lattice vectors. The self-assembled monolayer (SAM) contains many nonuniformities such as pinholes, domain boundaries, and monatomic depressions which are present in the Au surface prior to SAM adsorption. The detailed observations demonstrate limitations to the application of 1-nonanethiol as a resist in atomic nanolithography experiments to feature sizes of ∼20 nm.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Nature of Alkanethiol Self-Assembled Monolayer Adsorption on Sputtered Gold Substrates

2004

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“…These events are mutually dependent, which is similar to UHV-STM observations of the alkanethiol SAMs. However, white nano protrusions often found during alkanethiol SAM formation in UHV 109 are not observed by in situ STM. This suggests a different formation mechanism in the liquid environment.…”

Section: This Journal Is C the Owner Societies 2011mentioning

confidence: 86%

“…Both the formation dynamics including several intermediate phases and the steady-state SAM structures have been characterized by UHV-STM. [107][108][109][110][111] The advantages of such studies are to offer a fundamental understanding of the formation mechanism as well as the detailed surface structures of the SAMs. However, a broad range of SAMs have been prepared more practically using wet methods.…”

Section: Assembly Environmentsmentioning

confidence: 99%

Electrochemically controlled self-assembled monolayers characterized with molecular and sub-molecular resolution

Zhang

Welinder

Chi

et al. 2011

Phys. Chem. Chem. Phys.

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Self-assembled organization of functional molecules on solid surfaces has developed into a powerful and sophisticated tool for surface chemistry and nanotechnology. A number of reviews on the topic have been available since the mid 1990s. This perspective article aims to focus on recent development in the investigations of electronic structures and assembling dynamics of electrochemically controlled self-assembled monolayers (SAMs) of thiol containing molecules on gold surfaces. A brief introduction is first given and particularly illustrated by a Table summarizing the molecules studied, the surface lattice structures and the experimental operating conditions. This is followed by discussion of two major high-resolution experimental methods, scanning tunnelling microscopy (STM) and single-crystal electrochemistry. In Section 3, we briefly address choice of supporting electrolytes and substrate surfaces, and their effects on the SAM structures. Section 4 constitutes the major body of the article by offering some details of recent studies for the selected cases, including in situ monitoring of assembling dynamics, molecular electronic structures, and the key external factors determining the SAM packing. In Section 5, we give examples of what can be offered by theoretical computations for the detailed understanding of the SAM electronic structures revealed by STM images. A brief summary of the current applications of SAMs in wiring metalloproteins, design and fabrication of sensors, and single-molecule electronics is described in Section 6. In the final two sections (7 and 8), we discuss the current status in understanding of electronic structures and properties of SAMs in electrochemical environments and what could be expected for future perspectives.

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“…Such depressions are also characteristic of formation of both thiol-1 and selenol- 16 based SAMs on Au(111), and likely result mainly from lifting the Au(111) herringbone reconstruction upon chemisorption of these molecules. 17 Detection of similar features for alkynes suggests formation of densely packed chemisorbed structures on Au(111).…”

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confidence: 99%

Formation of Highly Ordered Self-Assembled Monolayers of Alkynes on Au(111) Substrate

et al. 2014

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Self-assembled monolayers (SAMs), prepared by reaction of terminal n-alkynes (HC C(CH 2 ) n CH 3 , n = 5, 7, 9, and 11) with Au(111) at 60°Cwere characterized using scanning tunneling microscopy (STM), infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), and contact angles of water. In contrast to previous spectroscopic studies of this type of SAMs, these combined microscopic and spectroscopic experiments confirm formation of highly ordered SAMs having packing densities and molecular chain orientations very similar to those of alkanethiolates on Au(111). Physical properties, hydrophobicity, high surface order, and packing density, also suggest that SAMs of alkynes are similar to SAMs of alkanethiols. The formation of high-quality SAMs from alkynes requires careful preparation and manipulation of reactants in an oxygen-free environment; trace quantities of O 2 lead to oxidized contaminants and disordered surface films. The oxidation process occurs during formation of the SAM by oxidation of the −CC− group (most likely catalyzed by the gold substrate in the presence of O 2 ).T hin organic films based on self-assembled monolayers (SAMs) 1 are ubiquitous in surface science. The reaction of organic thiols (RSH) with group Ib metals (Au and Ag) to generate SAMs with composition Au/AgSR is the reaction most commonly used to prepare SAMs, 1 although reactions that generate organosilanes on silicon 2 (SiR) and organic carboxylates on silver 3 (AgO 2 CR) have attractive properties, and a number of other precursors have been surveyed. There have also been scattered descriptions of SAMs formed on gold from solutions of alkynes 4 (HCC(CH 2 ) n CH 3 , n = 3, 5, 7, 9, 11, and 13), ethynylbenzene 5 (HCCC 6 H 5 ) or nalkylmercury(II) tosylates 6 (CH 3 (CH 2 ) n HgOTs, n = 4 and 18) on Au(111). Although the potential interest of SAMs having metal−CCR bonds is high, since they offer a new type of metal−organic bond, most of these studies have used preparations analogous to those employed with n-alkanethiols and have generated SAMs that do not seem to be highly ordered and, thus, are perhaps unsuitable for detailed studies of the physical chemistry of the surface. In particular, there are no procedures that describe the formation of SAMs that are highly ordered in two dimensionsa key requirement for high-quality surface science. The most recent analyses of n-alkyl-based SAMs on Au(111) indicate a "liquid-like" structure of the monolayer, 6 and XPS analyses of SAMs formed from alkynes 4,5 suggest that these SAMs are sensitive to oxidation at an undefined point in their formation; that is, oxidation occurs either during or after SAM formation (for example, by reaction of the AuCCR bond with O 2 ). Contact angle analyses of increasing lengths of alkynes (HCC(CH 2 ) n CH 3 , n = 5, 7, 9, and 11) also suggest 4 that the quality of these SAMs is lower than those based on n-alkanethiols.Although SAMs have enabled studies of wetting, 7,8 adhesion, 9,10 and charge transport 3,11−13 (...

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Mechanism of Formation of Au Vacancy Islands in Alkanethiol Monolayers on Au(111)

Cited by 327 publications

References 45 publications

The Nature of Alkanethiol Self-Assembled Monolayer Adsorption on Sputtered Gold Substrates

The Nature of Alkanethiol Self-Assembled Monolayer Adsorption on Sputtered Gold Substrates

Electrochemically controlled self-assembled monolayers characterized with molecular and sub-molecular resolution

Formation of Highly Ordered Self-Assembled Monolayers of Alkynes on Au(111) Substrate

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