MSE Seminar - Dr. Michael A . Filler, Chemical and Biomolecular Engineering, Georgia Tech

MSE Seminar
Event Date:
Monday, September 12, 2016 - 4:00pm
Location:
GTMI/Callaway Bldg. Auditorium

Dr. Michael A. Filler

Associate Professor and Gunn Faculty Fellow

School of Chemical & Biomolecular Engineering

Georgia Institute of Technology 

Monday, September 12, 2016

4:00 p.m. GTMI/Callaway Bldg. Auditorium

Reception at 3:30 p.m. in the GTMI Atrium 

The Vapor-Liquid-Solid Mechanism:

Encoding Heterogeneity at the Nanoscale

Abstract:

Controlled compositional heterogeneity is central to the operation of devices ranging from field effect transistors to solar cells. It is also critical for advanced materials where the arrangement of constituent elements gives rise to exotic properties. Semiconductor nanowire synthesis via the vapor-liquid-solid (VLS) mechanism – whereby a liquid eutectic “catalyst” droplet collects precursor molecules from the vapor and directs crystallization of the solid nanowire – permits the requisite programming of composition at the nanoscale. However, in many cases, it still remains challenging to precisely control nanowire structure and function. To this end, we combine in situ infrared spectroscopy and electron microscopy to probe the heterointerfacial chemical processes that govern nanowire growth. Our studies reveal the presence and dramatic influence of various adsorbed species. We find, for example, that changes to hydrogen atom coverage on the nanowire sidewall can control catalyst phase, atomic transport to/from the catalyst, heterostructure formation, nanowire growth direction, and tapering. These insights not only provide guidelines for advancing synthetic design, but also enable a previously unattainable level of nanoscale fidelity and functionality

Bio-sketch

Dr. Filler is an Associate Professor and the Gunn Faculty Fellow in the School of Chemical &

Biomolecular Engineering at the Georgia Institute of Technology. He earned his undergraduate

and graduate degrees from Cornell University and Stanford University, respectively, prior to

completing postdoctoral studies at the California Institute of Technology. Dr. Filler’s research

program lies at the intersection of chemical engineering and materials science, focusing on the

synthesis, understanding, and deployment of nanoscale materials for applications in electronics,

photonics, and energy conversion. The use of in situ infrared spectroscopy to interrogate the

interfacial chemistry governing semiconductor nanowire growth, crystal structure, and properties

is a major component of his work. Dr. Filler has been recognized for his research and teaching

with the National Science Foundation CAREER Award, Georgia Tech Sigma Xi Young Faculty

Award, CETL/BP Junior Faculty Teaching Excellence Award, and as a Camille and Henry 

Dreyfus Foundation Environmental Chemistry Mentor.