Subtractive Patterning via Chemical Lift-Off Lithography

Liao, Wei‐Ssu; Cheunkar, Sarawut; Cao, Huan H.; Bednar, Heidi R.; Weiss, Paul S.; Andrews, Anne M.

doi:10.1126/science.1221774

Cited by 147 publications

(271 citation statements)

References 49 publications

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“…For the reduced gold surface, the force histogram indicates a most probable rupture force of 0.62±0.18 nN. Previous studies 5,27,[30][31][32]34,43,44 strongly indicated that the breakage takes place at the Au-Au bond around the Au-S binding sites, which was the weakest among the covalent bonds (that is, Si-O, Si-C, C-N, C-C, C-O, Au-S and Au-Au) in the linkage, leaving one or more gold atoms at the terminal of the tethered linker. Control experiments, in which the thiolterminated PEG was replaced with sulphur-free methoxylterminated PEG, were performed to confirm that the rupture force obtained above originated from the interaction between the sulphydryl group and gold surfaces.…”

Section: Resultsmentioning

confidence: 95%

“…SAMs that are based on thiol-gold chemistry have been widely employed in the fields of chemistry, physics, molecular biology, pharmaceutical engineering and materials science [1][2][3] . Considerable interests in such systems have increased, owing to their versatile applications, including the fabrication of nanopatterning 4,5 , molecular-scale devices 6,7 , optical materials 8,9 , formulation of biosurfaces 10 and support for cell culture 2,11 . The strength of the gold-sulphur (Au-S) interaction formed between thiols and gold surfaces provides the basis to fabricate robust SAMs for diverse applications.…”

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confidence: 99%

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Quantifying thiol–gold interactions towards the efficient strength control

et al. 2014

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The strength of the thiol-gold interactions provides the basis to fabricate robust self-assembled monolayers for diverse applications. Investigation on the stability of thiol-gold interactions has thus become a hot topic. Here we use atomic force microscopy to quantify the stability of individual thiol-gold contacts formed both by isolated single thiols and in self-assembled monolayers on gold surface. Our results show that the oxidized gold surface can enhance greatly the stability of gold-thiol contacts. In addition, the shift of binding modes from a coordinate bond to a covalent bond with the change in environmental pH and interaction time has been observed experimentally. Furthermore, isolated thiol-gold contact is found to be more stable than that in self-assembled monolayers. Our findings revealed mechanisms to control the strength of thiol-gold contacts and will help guide the design of thiol-gold contacts for a variety of practical applications.

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Section: Resultsmentioning

confidence: 95%

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confidence: 99%

Quantifying thiol–gold interactions towards the efficient strength control

et al. 2014

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“…The monolayers studied consist of undecanethiol alkyl chains that are chemically bound to an Au(111) surface. After the deposition of alkyl chains, the rhenium carbonyl vibrational probe (fac-Re(phenC≡CH)(CO) 3 Cl) is attached to the monolayer via a Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction ("click" chemistry). In addition to the head group rhenium carbonyl complex (the vibrational probe), there is also a triazole ring, which is formed during the cycloaddition reaction (Fig.…”

Section: Static Structure Of Gold Samsmentioning

confidence: 99%

Unraveling the dynamics and structure of functionalized self-assembled monolayers on gold using 2D IR spectroscopy and MD simulations

Yan

Yuan

Pfalzgraff

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Functionalized self-assembled monolayers (SAMs) are the focus of ongoing investigations because they can be chemically tuned to control their structure and dynamics for a wide variety of applications, including electrochemistry, catalysis, and as models of biological interfaces. Here we combine reflection 2D infrared vibrational echo spectroscopy (R-2D IR) and molecular dynamics simulations to determine the relationship between the structures of functionalized alkanethiol SAMs on gold surfaces and their underlying molecular motions on timescales of tens to hundreds of picoseconds. We find that at higher head group density, the monolayers have more disorder in the alkyl chain packing and faster dynamics. The dynamics of alkanethiol SAMs on gold are much slower than the dynamics of alkylsiloxane SAMs on silica. Using the simulations, we assess how the different molecular motions of the alkyl chain monolayers give rise to the dynamics observed in the experiments.self-assembled monolayer | dynamics | 2D IR spectroscopy | MD simulation S elf-assembled monolayers (SAMs) on planar metal surfaces enable the tailoring of interfacial properties by functionalization of the alkyl chains. SAMs formed by alkanethiol chains on gold surfaces are of particular interest due to the ordered packing of the chains, chemical stability, and facile methods of preparation, as well as the diverse array of chemical functionalization that can be added (1). The properties of SAMs on gold have led to applications including electrochemical devices (2), surface patterning (3), model biological surfaces (4), and heterogeneous catalysis (5). In many of these applications, the interfacial properties of the monolayer are determined largely by the particular head group linked at the terminal site of the alkyl chain.The structure of SAMs on gold has been well characterized by scanning probe microscopy (6), helium diffraction (7), X-ray photoelectron spectroscopy (8), sum-frequency generation spectroscopy (SFG) (9), and linear infrared spectroscopy (10). However, to determine how the physical and chemical properties of SAMs are related to their microscopic dynamics and structure and the influence of head groups present in most applications, fast time-resolved experimental techniques, with sufficient selectivity and sensitivity, are required to measure the structural dynamics of a monolayer of molecules on the appropriate picosecond (ps) timescale.Two-dimensional infrared vibrational echo spectroscopy (2D IR) provides the necessary observables by measuring spectral diffusion, i.e., the time-dependent evolution of the probe vibrational frequency in response to structural fluctuations of the chemical environment (11-13). To use 2D IR to investigate monolayer dynamics requires selectivity for the interfacial region. One method to achieve this is to combine 2D IR spectroscopy with SFG (14, 15), which requires a vibrational mode that has both a large IR transition dipole and a large Raman cross-section. However, for a monolayer functionalized with the vibra...

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“…For high‐resolution nanopatterns a number of techniques are well developed, including electron‐/ion‐beam‐based lithography1, 2, 3 and tip‐based lithography,4, 5, 6, 7, 8, 9 but they are often too slow for wafer‐scale processes that demand fast processing times. On the other hand, for large‐area nanopatterning, optical/plasmonic lithography,10, 11, 12, 13, 14, 15 contact printing‐based lithography,16, 17, 18, 19 and template‐assisted lithography20, 21, 22, 23 are promising candidates; however, they require additional expensive and time‐consuming pre‐fabrication processes, such as the preparation of a master template. Colloidal lithography including nanosphere lithography (NSL),24 nanoparticle lithography,25, 26 and block copolymer micelle nanolithography (BCML)27 are attractive large‐scale parallel patterning methods that permit time‐ and cost‐effective patterning at the wafer‐scale.…”

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confidence: 99%