WIN Seminar - Professor Jan Dubowski "Photocorrosion of functionalized GaAs/AlGaAs nano-heterostructures"

Wednesday, August 3, 2016 3:00 pm - 4:00 pm EDT

The Waterloo Institute for Nanotechnology (WIN) presents a seminar by Professor Jan Dubowski, holder of the Canada Research Chair in Quantum Semiconductors and a Fellow of the International Society for Optical Engineering from the Department of Electrical and Computer Engineering at Universite de Sherbrooke, Quebec.

Photocorrosion of fictionalised GaAs/AlGaAs nano-heterostructures


III-V semiconductors have played key role in the development of optoelectronic, fast speed microelectronic, photovoltaics and some other photonic devices. However, the sensitivity of these materials to moisture and oxygen, e.g., the photocorrosion of GaAs in aqueous solutions is a known drawback limiting the use of this material for solar energy-conversion, requires application of surface protecting physical and/or chemical methods. If induced to proceed at a nanoscale rate, the photocorrosion of GaAs/AlGaAs heterostructures reveals a measurable sensitivity to the presence of electric charge accumulating at their surfaces. Functionalization of the GaAs surface with alkanethiol self-assembled monolayers allows working with architectures designed for specific immobilization of charged molecules in the vicinity of a photocorroding surface. I will discuss the conditions required to control photocorrosion of GaAs/AlGaAs heterostructures at the nanoscale rate, and I will demonstrate the application of a photoluminescence monitored photocorrosion to sensing electrically charged bacteria immobilized on functionalized surfaces of GaAs/AlGaAs nano-heterostructures. In addition to the rapid detection of bacteria, the photocorrosion-based approach has enabled us to investigate the reaction of bacteria captured on the GaAs surface (yes, bacteria can grow on GaAs) to ciprofloxacin and penicillin environments. The mechanisms of electric charge moderated photocorrosion and a perspective of this approach for rapid evaluation of bacterial reactions with different antibiotics will also be discussed.