Physics Colloquium: Pores, Particles, Fibres, and Films: Tailored Nanostructures ...

Thursday, January 26, 2017

3:30 PM-4:30 PM

Jason R. Dwyer, PhD, University of Rhode Island

 

Pores, Particles, Fibres, and Films: Tailored Nanostructures for Charged-Particle Single-Molecule Sensing and Spectroscopy

Nanostructures underpin our efforts at exploring molecular-level phenomena and the physicochemical properties of the players. Our research builds from nanofabrication technique development to the design, fabrication, characterization, and application of nanoscale devices. A vital offshoot of this effort is the development of new experimental methods that fully leverage the unique capabilities of the tailored devices. We have a particular interest in approaches that bridge conventional and unconventional materials and processes, and that maximize—often by repurposing and augmenting—the performance capabilities of those materials. Top-down nanofabrication using free-standing silicon nitride thin films yields a nanofluidic device that enables straightforward transmission electron microscopy (TEM) studies, including real-time nanoscale movies showing structural dynamics, of liquid-bathed samples. The same thin films can be bestowed, through bottom-up approaches, a <<100 nm-long through-channel—a nanopore—capable, by using ion reporters, of all-electronic single-molecule sensing and characterization. Method development, coupled to nanofabrication, can enable the nanopore to probe intermolecular interactions—most strikingly through a technique known as nanopore force spectroscopy. Surface chemical modifications figure prominently in our efforts, and include spatially-controlled, solution-based electroless plating, and direct photochemical modification of surfaces. We used the ability of electroless plating to generate metals films, with nanoscale grains, on even highly structured surfaces to turn, for example, a host of materials including porous, thin silicon nitride membranes and paper into substrates for surface enhanced Raman spectroscopy (SERS). In this talk, I will present examples of in-liquid TEM, nanopore sensing, and SERS sensing, and describe the nanotechnology behind our explorations of the molecular world.

Contact Information

Professor Maher Harb
maher.harb@drexel.edu