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Process Database

The InterNano Process Database is a knowledge base of techniques for processing nanoscale materials, devices, and structures that includes step-by-step descriptions, images, notes on methodology and environmental variables, and associated references and patent information.

The purpose of the Process Database is to facilitate the sharing of appropriate process knowledge across laboratories.The processes included here have been previously published or patented.

If you have a published and/or patented process that you would like to include in the InterNano Process Database, you can either contact us and we will add the process for you, or you can register on InterNano and add the process yourself.

Roll-to-Roll Electrophoretic Deposition of Hybrid Nanomaterials

Presented here is a method for assembling homogenous films of controllable thickness comprised of hybrid nanostructures on a roll-to-roll platform directly from solution. Using surfactant-free mixtures of nanoparticles, nanotubes, nanosheets, and any combination thereof, film fabrication may be achieved that maintains the chemical and physical properties inherit to the constituent material that is not limited by the presence of surfactants or impurities. Using this technique, researchers may demonstrate the viability of scalable production of a synthesized material.

ZnO nanorods on paper substrate. Image reproduced with permission from Manekkathodi, et. al. 2010. Direct Growth of Aligned Zinc Oxide Nanorods on Paper Substrates for Low-Cost Flexible Electronics. Advanced Materials 22(36): 4059-4063. http://dx.doi.org/10.1002/adma.201001289.
Direct Growth of Aligned Zinc Oxide Nanorods on Paper Substrates

A method for the controlled direct growth of highly crystalline ZnO nanorods on a paper substrate is described. Despite the complexity and surface roughness which paper naturally presents, adequate surface modification enhances ZnO nanorod alignment and uniformity in growth. Large scale synthesis is also demonstrated. Hybrid PN junction diodes, also on paper substrates, show application toward flexible electronics.

(a) Scheme depicting the process for dry contact transfer of aligned SWNTs as described in the text. (b) SEM image of an upright patterned growth prior to transfer, and (c) picture showing a complete transfer to a 5 mm × 5 mm wide diamond window.
Aligned Carbon Nanotube Patterning Via Dry Contact Transfer Printing

The approach of transferring CNT thin films from one surface to another via a soft lithography technique suffers from limited ability to achieve good adhesion of the CNT films to the transferred substrate and imprecise alignment of the CNT patterns. A transfer technique  that can be scaled to large area with high throughput processing at low temperature is being reported in this paper, demonstrating a scalable means to create aligned CNT thin film patterns on both rigid and flexible substrates.

Chip schematic. (a) illustrates the bias electrode used for applying the bias potential from the arbitrary function generator and the counter electrodes, which are capacitively coupled to the conductive substrate except for one, which is directly coupled to the ground. Inset (b) shows in detail the finger electrodes in yellow, over which the two-dimensional graphene nanostructures will bridge. The cross section of the finger electrode gap is depicted in (c). Reprinted from Burg BR, Lutolf F, Schneider J, Schirmer NC, Schwamb T, Poulikakos D. 2009. High-yield dielectrophoretic assembly of two-dimensional graphene nanostructures. Applied Physics Letters. 94(5). Permission pending.
High-yield dielectrophoretic assembly of two-dimensional graphene nanostructures

The serial mechanical exfoliation method available can not be used for the assembly of graphene in the large scale. In this process, deposition of ultrathin few-layer (three to ten) graphene oxide, with parallel and controllable assembly, by dielectrophoresis between prefabricated electrodes has been demonstrated.

Reprinted with permission from Torrisi F, Hasan T, Wu W, Sun Z, Lombardo A, Kulmala TS, Hsieh GW, Jung S, Bonaccorso F, Paul PJ, Chu D, Ferrari AC. 2012. Inkjet-printed graphene electronics. ACS Nano. Article ASAP. Copyright 2012 American Chemical Society
Inkjet-printed graphene electronics

Inkjet printing is a promising technique for printing of electronic materials and devices over large areas on flexible substrates. Inkjet printing is a versatile approach involving a limited number of steps with the ability to deposit controlled amounts of material. The development of inks for inkjet printing can be tailored to optimize the properties of the printed films and structures, and are additionally versatile in that virtually any nanomaterial composition can be incorporated as long as the nanostructure size is sufficiently small that the inkjet nozzle does not become clogged.

Dotted line: electrode potential, solid line: current, dashed line: EQCM frequency change
Pulse-reversed electrodeposition with QCM monitoring to make magnetic nanowires in a nanotemplate

Cobalt nanowires with high perpendicular magnetic anisotropy are formed in a diblock copolymer film template using a pulse-reversed voltage with QCM monitoring.  This in situ monitoring system along with the pulse-reversed field enables new control over the magnetic crystal growth.

Fabrication of a nanoporous template from a diblock copolymer film - neutral brush

A perpendicular orientation of cylindrical microdomains in diblock copolymer thin films is achieved by control over polymer-surface interactions. The block which forms cylindrical microdomains is removed by UV exposure and a chemical rinse to yield a nanoporous polymer film. The porous film can be used as a template for electrodeposition of metal nanodots or as a mask for reactive ion etching.

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Process Database - Unpublished

SEM images of TiO2  nanowires grown using 10 mL of DI water, 10 mL of HCl, and 1 mL of TiCl4 at 180C for 4 h on different substrates. (a) FTO substrate, top view. (b) FTO substrate, cross-sectional view. (c) Glass substrate, top view. (d) Glass substrate, perspective view. (e) ITO substrate, top view. (f) ITO substrate, perspective view. (g) Si/SiO2  substrate, top view. (h) Back side of the TiO2  film peeled off from the Si/SiO2  substrate. In every image, the inset shows the corresponding nanowires at higher resolution.
Growth of Aligned Single Crystalline Rutile TiO2 Nanowires on Arbitrary Substrates and Their application in Dye-Sensitized Solar Cells.

A process for growing single-crystalline rutile phase TiO2 nanowires on arbitrary substrates, including fluorine-doped tin oxide (FTO), glass slides, tin-doped indium oxide (ITO), Si/SiO2, Si(100), Si(111), and glass rods. Various morphologies of nanowires can be achieved by varying growth parameters such as temperature, growth time, precursor concentrations and substrate positioning.

Hybrid Passivated Colloidal Quantum Dot Solids

A colloidal quantum dot hybrid passivation scheme that utilizes halide anions during the synthesis process to passivate trap sites that are inaccessible to much larger organic ligands. This scheme is demonstrated in solar cell fabrication, leading to a certified efficiency of 7.0%.

Controlled Ultrathin Films of Carbon Nanotubes for Electrochemical Applications

Films of vertically aligned CNTs prepared by chemical vapor deposition have previously been demonstrated, but their usefulness is limited by low density and high porosity.Solution processes for forming polymer-CNT nanocomposites are another method to form dense films, yet they suffer from precipitation into bundles due to strong van der Waals interactions between CNTs.Layer-by-layer (LBL) assembly, which was explained in this paper, is a versatile method to form dense thin films from dispersed solutions containing functionalized nanomaterials.

SSLbL schematic. Step 1a-e shows the deposition of a negatively charged material (nanoclay), and step 2a-e shows the same cycle repeated for a positively charged polymer.
Fast, simple and efficient assembly of nanolayered materials and devices

This is a new method of ‘directed’ self-assembly. It has the potential to simply and quickly build nanostructured materials and devices. This method is also called as spin–spray layer-by-layer self-assembly (SSLbL). It is possible to create and stack nanometer-thick, uniform layers containing a wide variety of different polymers, nanoparticles, or colloids in less than 25 s per bilayer, orders of magnitude faster than traditional LbL, using SSLbL. SSLbL is also much less wasteful of valuable nanoparticles and polymers than LbL.

Progress Towards High-Throughput Continuous Nanoimprinting

Roll-to-Roll and Roll-to-Plate processes has been demonstrated, which help in integration of emerging nanomanufacturing techniques with high throughput production infrastructure.It can overcome the challenges faced by conventional NIL in maintaining pressure uniformity and successful demolding in large-area imprinting.

Ultrahigh density alignment of carbon nanotube arrays by dielectrophoresis

The process, called Dielectrophoresis, by which single-walled carbon nanotube can be assembled, is mentioned in this paper.The SWCNT's are available in the form of surfactant-free and stable solutions.They also showed a method to control the linear density of SWCNT's s from 0.5 SWNT/¼m to more than 30 SWNT/¼m by optimization of frequency ,trapping time and by tuning the concentration of the nanotubes in the solution.

SEM surface morphology of (a) [PSSþSWNT/PVA]30 by dip-LbL, (b) [(PSSþSWNT)0.5/PVA0.5]30, (c) [(PSSþMWNT)0.5/ PVA0.5]30, (d) [(NafionþSWNT)0.5/PEI0.5]30, and (e) [(PSSþSWNT)0.5/PANI0.5]30.
Improving the assembly speed, quality, and tunability of thin conducting multilayers

Thin functional films have traditionally been produced by low-tech processes such as casting and dip-coating, but these methods are both slow and offer a low level of control over film properties. An alternative scheme is layer-by-layer assembly (LbL), but this process takes longer time. The spin-spray layer-by-layer (SSLbL) assembly technique has been introduced in this paper which provides solution for the drawbacks of all the processes mentioned above in addition to decreasing the material waste and enhance the control over film thickness.