Three-Dimensional Nanostructure Construction via Nanografting:  Positive and Negative Pattern Transfer

Abstract

Three-dimensional nanostructures can be constructed using scanning probe lithography in combination with selective surface reactions. This letter introduces a successful approach using AFM-based nanografting to produce two-dimensional nanopatterns within self-assembled monolayer resists. These nanopatterns serve as an anchor to construct nanostructures in the third dimension via surface reactions. In this way, the nanometer-scale 2D pattern is transferred to chemically distinct 3D nanostructures. This approach offers the advantages of high spatial precision and selectivity in pattern transfer.

Achieving Precision and Reproducibility for Writing Patterns of n‐alkanethiol Self‐assembled Monolayers with Automated Nanografting

“…Analogous to time-lapse photography, after writing nanopatterns further reactions can be conducted selectively on spatially defined regions of the surface with nanoscale control of the reactivity of SAM headgroups. The surrounding areas of a matrix SAM can be chosen to provide a nonreactive or insulating headgroups to spatially direct reactions to occur only for the nanografted areas (Liu et al ., 2002b).Within the liquid cell, solutions can be introduced with fresh reagents and molecules for surface-confined reactions. Sequential real-time AFM images display reaction steps at a molecular level, providing details of the adsorption and conformational changes that take place over time (Wadu-Mesthrige et al ., 2001).…”

“…Also, SAM patterns produced by nanografting can serve as a molecular ruler for local measurements of the thickness of films (Brower et al ., 2002;Yu et al ., 2006;Kadalbajoo et al ., 2007).The desorption and stability of nanografted patterns over time has been investigated for different spacer lengths of n-alkanethiol SAMs . Bottom-up assembly has been accomplished to produce 3-D nanostructures by reactions with octadecyltricholorosilane (Liu et al ., 2002b), and electroless deposition of copper has been achieved selectively on SAM nanopatterns ). An emerging area of research is enabled for molecular-level investigations of biochemical reactions with nanografted protein structures in which nanopatterns are monitored during in situ protocols in aqueous buffers (Wadu-Mesthrige et al ., 1999, 2000Kenseth et al ., 2001;Case et al ., 2003;Cheung et al ., 2003;Zhou et al ., 2003;Hu et al ., 2005).…”

“…In situ investigations with nanografting have been reported for adsorption of proteins (Wadu-Mesthrige et al ., 1999, 2000Kenseth et al ., 2001;Case et al ., 2003;Cheung et al ., 2003;Jang et al ., 2003;Zhou et al ., 2003), electroless deposition of copper on nanografted gradients of carboxylate-terminated SAMs , and for pattern transfer reactions with polymers. (Liu et al ., 2002b) Despite the intrinsic in situ advantages and capabilities for high spatial resolution, nanografting has not yet become widely applied for surface investigations as compared to other ambient ex situ writing methods. The complexity of imaging in liquids requires advanced skills and training for experimentalists.…”

Additive nanomanufacturing – A review

“…Taking advantage of the positioning resolution enabled by piezo-actuation and the nanoscale radii of the tips, scientists were able to generate sub-50-nm features by scratching, etching and oxidizing surfaces. 28 A process known as nanoshaving or nanografting uses the tip of an AFM and an applied force to remove a molecular monolayer on gold in a site-specific fashion 29 and anodic oxidation of silicon was developed by Quate and colleagues for patterning silicon substrates. 30,31 In contrast to nanoshaving and nanografting DPN selectively transfers material from an ink coated probe tip on to a surface with a variety of ink-surface combinations.…”

Nanolithography: Towards Fabrication of Nanodevices for Life Sciences

“…Nanografting was first invented in 1997 and combines nanoshaving with the simultaneous replacement of matrix SAM molecules by the self-assembly of new molecules [54,67]. A broad range of thiolated molecules have been nanografted to provide tremendous flexibility in choosing the desired molecular lengths and terminal groups for experimental designs [68][69][70][71][72]. This section describes the procedure for nanografting SAMs, presents an example using automated nanografting with SAMs and then reviews examples which apply force-induced lithography (nanografting) for protein patterning.…”