Abstract:
In 1964 Wagner and Ellis presented the first paper on fabrication of micron-scale semiconductor whiskers. Our group was one of the first to apply their ideas in the late 1990’s to realise nanowires with diameters of tens of nanometers. We show how strong dielectric confinement, coupled with weak screening in structures of these dimensions presents a unique opportunity for realizing field effect transistor chemical sensors. In particular, we focus on InAs nanowires having exceptional transport properties combined with a nature surface accumulation layer which we show can mediate sensing. Indeed, we showed how electrometry can be performed with such devices to sense charge to levels as low as tens of micro-electron charges per root hertz bandwidth. With such a response, the transduction of adsorption events into electrical signals is shown to permit single molecule level sensing.
Biography:
Harry Ruda is Stanley Meek Chair in Nanotechnology and Director, Centre for Advanced Nanotechnology at U. Toronto. He obtained his BSc from Imperial College and his PhD from MIT on optical and transport properties of II-VI materials in 1982. As an IBM postdoctoral fellow, he developed one of first theories for electron transport in selectively doped 2DEGs and at 3M Corporation, spearheaded the blue laser team. In 1989 he joined the U. Toronto and currently has over 300 publications (with over 8,344 citations; h=45), has co-authored 4 books and has 14 patents. His interests focus on nanostructures with application in areas such as sensing and quantum technology. He has served on government panels including NSERC, DOE, EPA, NSF, RAE and EPSRC, and editorial boards of: J. Appl. Physics, Appl. Physics Letters, J. Nanoscience and Nanotechnology, J. Materials Science: Materials in Electronics, Nanotechnology Research Letters, and Nano-Micro Letters and is currently Chief Editor of IET-CDS. He is a Fellow of Royal Society of Canada, Institute of Physics, Institute of Nanotechnology, IET, and Canadian Academy of Engineering.
