MSE Colloquium: Andrew Gamalski, Real Time Transmission Electron Microscopy Studies of Nanowire Growth

Goldhaber Postdoctoral Fellow, Center for Functional Nanomaterials, Brookhaven National Laboratory

Abstract

With microscopy techniques such as environmental transmission electron microscopy (ETEM), it is possible to study the synthesis of multi-component material systems in real time and at high spatial resolution. Specifically silicon, germanium, and gallium nitride nanowires (NWs) are ideal model systems to study fundamental physical/chemical materials science processes at the nanometer scale. In addition to being a model system, catalytically grown NWs have potential applications in chemical sensors, solid state lighting, and battery materials. Using ETEM, several key aspects several key aspects of NW growth have been directly observed including: the initial nucleation of the semiconductor wire, growth from lattice resolved solid catalyst particles, dynamics at the catalyst-wire-vapor interface, and influence of defects on growth. These studies illustrate how NWs and ETEM can provide a means of analyzing several  fundamental materials science phenomena including: behavior of eutectic systems, solid-liquid interface dynamics, surface diffusion, phase nucleation, and crystal growth.

Bio

Andrew Gamalski is currently a Goldhaber Postdoctoral Fellow at Brookhaven National Laboratory. His current research focuses on the fundamentals of semiconductor nanowire crystal growth and operando studies of heterogeneous catalysts. He received his undergraduate in physics and mathematics at Arizona State University, and his PhD in Electrical Engineering at the University of Cambridge, where he studied semiconductor nanowire growth as a 2009 Marshall Scholar. After his PhD, Andrew worked at Intel Corporation as a failure analysis engineer developing laboratory instrumentation and running a laser micromachining system.