Semiconductor Nanowires: From Energy Harvesting to BioChemical Sensing

Semiconductor nanowires allow quantum confinement in two dimensions while allowing propagation of photons and carriers in the third. Thus, they exhibit very interesting optical properties including resonant excitement of optical modes resulting in enhanced absorption; excitation of longitudinal and lateral modes resulting in structural colors; electric field confinement resulting in enhanced non-linearities like Raman Scattering; ability to easy bandgap engineering through 3-dimensional electric field confinement; and new quantum behavior like switching from direct to in-direct bandgap with strain. This talk will cover the work done at University of Waterloo in fabrication, characterization, and device designs for vertical and lateral silicon and Gallium Arsenide nanowires. Enhanced absorption peaks; enhanced Raman scattering; second harmonic generation in silicon nanowires; resonant absorption in silicon and GaAs nanowires; highly sensitive photodetectors; negative capacitors; and structural color generation and its use in simple bio-chemical sensing will be discussed.
Simarjeet Singh Saini is an Associate Professor in the Department of Electrical and Computer Engineering and a member of the Waterloo Institute of Nanotechnology at the University of Waterloo. He is also founder and CTO of VidyaSmart Inc., a start-up developing low cost experimental hardware for hands-on education. He did his B.Tech (Hons.) from IIT, Kharagpur and PhD from University of Maryland. Previously, he has been involved in multiple start-up companies. Devices designed and developed by him are used in a majority of optical labs worldwide. He is founder of Edna Staebler Young Scientists Club and is actively involved in science and educational outreach to high school students. He has over 150 publications in areas ranging from nanophotonics, nanofabrication, photonics integration, and optical science and engineering.