Talha Arshad

Bottom-Up Techniques for Scalable Nanofabrication

If the vast promise of nanotechnology in all its different potential applications is to be realized, processes for the fabrication of a variety of nanostructures reliably and cost-effectively at industrial scales need to be developed. My research focuses on developing novel bottom-up methods to address this challenge.

Plasmonic devices, which exploit the way light interacts with metallic nanostructures, have applications ranging from solar cells to biosensors. Their widespread use is inhibited by the fact that many existing nanofabrication methods are not amenable to metals.

Schematic of templated evaporative lithography

Schematic of templated evaporative lithography

To this end I have proposed a process which uses natural evaporation to drive flow in a suspension of nanoparticles, resulting in a patterned deposit which can be sintered to yield a stable structure. This is achieved by using a topographically patterned membrane to mediate the rate of evaporation in different parts of the suspension film.  I have developed analytical models and finite element simulations to study the dynamics of the process and identify ideal process parameters.  I am currently working towards its experimental validation.

Another process I am working on relies on flow and electric fields to position and align nanowires on a substrate. This is important in nanowire and nanotube transistors, which have been identified as a promising way to continue the trend of increasing speed and compactness of our computing devices we have become used to. Such a method to deposit nanowires has been shown to be an effective one, but achieving the desired density has been challenging. I am developing Brownian Dynamics simulations to study ways to address this issue.

I have also collaborated with experimental research groups to develop finite element models for processes in oxygen-mediated cell growth and surface-tension mediated patterning of polymer films.

Publication:

Arshad, T.A., Bonnecaze, R.T., 2012, Templated evaporative lithography for high throughput fabrication of nanopatterned films, Nanoscale, 5(2), 624-633.