Solid state electrochemical processes for nanofabrication

Metallic nanostructures play a defining role in micro and nanotechnology, from interconnects in electronics to electrodes in chemical sensors, batteries, fuel-cells, antennae, plasmonic waveguides in sub-wavelength optics and structural color generation. While the demand for making functional metallic nanostructures for the development and commercialization of new technologies is increasing, there is a need for new manufacturing techniques that allow rapid prototyping or mass production of nanostructured devices at an economical and cost effective rate while using simple processing environments (i.e. liquid free, mask free, single step and ambient processing). To address these challenges, this thesis primarily examines solid state nano manufacturing pathways using ion conductive solid electrolytes, to develop a cost effective, simple alternative to state of the art direct writing techniques (e.g. Ebeam lithography and Focus ion beam lithography). First, a solid state electrochemical direct writing technique is developed using a conductive atomic force microscopy (AFM) tip for rapid prototyping of silver nanostructures on a silver based ion conductive glass substrate. The technique was implemented to fabricate silver nanostructures by using an AFM probe as the working electrode and ionically conductive glass (AgI)0.25(AgPO3)0.75 as the solid electrolyte in an electrochemical cell configuration. While the tip based approach was primarily adapted to explore time-scale and resolution capabilities with probe based writing, erasing of a silver pattern from the surface was also accomplished by scanning the surface using the AFM tip with anodic polarity. By using the patterned silver substrate as a template for replica molding of soft materials such as polydimethylsiloxane (PDMS), the writing technique was then utilized for single step integration of micro-channels with nano-channels. Next, this technique was extended to nano-patterning copper by utilizing a glassy copper pure ionic conductor ((CuI)x-(CuPO3 )(1-x) from the same family of solid electrolytes. To address manufacturing needs on an industrial scale, our laboratory has previously developed an imprint based scalable manufacturing process using solid electrolytes known as solid-state superionic stamping (S4) to selectively etch silver and copper. The technique currently allows the fabrication of sub-100 nm features on a planar surface over an area of 0.26 mm2 and micron scale features over an area of 25 mm2. The later part of this thesis demonstrates S4 patterning over an area of 100 mm2 and discusses the potential of further scaling up the S4 process using large area stamps. S4 patterning of silver using a roll to plate scheme is also demonstrated to explore the potential of the S4 technology in a roll to roll configuration for high volume manufacturing. Additionally, the opportunities to advance the S4 technology with the aid of a commercially available two photon lithography based direct writing technique from Nanoscribe is also investigated. First, the unique capability of the two photon lithography (2PP) process to introduce height variation at the nanoscale is explored for fabricating meta-surface based planar focusing solar collectors. The prospect of the 2PP process is then investigated as a means for preparing mold substrates for S4 and enabling 3D metallic nanostructures of silver.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2018

Author dc:creator

• Barna, Shama Farabi

Contributors dc:contributor

• Ferreira, Placid M.
• Aluru, Narayana R.
• Toussaint, Kimani C.
• Shoemaker, Daniel P.

• Nanofabrication,Solid Electrolytes, Electrochemical Nanopatterning

Statement dc:rights

• Copyright 2018 Shama Barna

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/101262

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/101262