Nanocontact electrification: patterned surface charges affecting adhesion, transfer, and printing.

Contact electrification creates an invisible mark, overlooked and often undetected by conventional surface spectroscopic measurements. It impacts our daily lives macroscopically during electrostatic discharge and is equally relevant on the nanoscale in areas such as soft lithography, transfer, and printing. This report describes a new conceptual approach to studying and utilizing contact electrification beyond prior surface force apparatus and point-contact implementations.

Nanocontact electrification through forced delamination of dielectric interfaces.

This article reports patterned transfer of charge between conformal material interfaces through a concept referred to as nanocontact electrification. Nanocontacts of different size and shape are formed between surface-functionalized polydimethylsiloxane (PDMS) stamps and other dielectric materials (PMMA, SiO(2)). Forced delamination and cleavage of the interface yields a well-defined charge pattern with a minimal feature size of 100 nm.

Mimicking electrodeposition in the gas phase: a programmable concept for selected-area fabrication of multimaterial nanostructures.

An in situ gas-phase process that produces charged streams of Au, Si, TiO(2), ZnO, and Ge nanoparticles/clusters is reported together with a programmable concept for selected-area assembly/printing of more than one material type. The gas-phase process mimics solution electrodeposition whereby ions in the liquid phase are replaced with charged clusters in the gas phase. The pressure range in which the analogy applies is discussed and it is demonstrated that particles can be plated into pores vertically (minimum resolution 60 nm) or laterally to form low-resistivity (48 microOmega cm) interconnects.

Fringing field directed assembly of nanomaterials.

This letter reports on a new gas-phase printing approach to deposit nanomaterials into addressable areas on a surface with 50 nm lateral accuracy. Localized fringing fields that form around conventional resist patterns (PMMA and SiO2) with openings to a silicon substrate are used to direct the assembly of nanomaterials into the openings. Directed assembly was observed due to a naturally occurring inbuilt charge differential at the material interface that was further enhanced by corona charging to yield a field strength exceeding 1 MV/m in Kelvin probe force microscopy (KFM) measurements.

Charging process and Coulomb-force-directed printing of nanoparticles with sub-100-nm lateral resolution.

This article reports on a new charging process and Coulomb-force-directed assembly of nanoparticles onto charged surface areas with sub-100-nm resolution. The charging is accomplished using a flexible nanostructured thin silicon electrode. Electrical nanocontacts have been created as small as 50 nm by placing the nanostructured electrode onto an electret surface.