Detection and quantification of very small amounts of biological species become necessary to allow an early detection of biothreats. Currently, fluorescence detection and colorimetry are the most frequently used techniques. Although very sensitive, the necessary labelling step of the biotargets can alter their recognition properties and these methods have a low potential for integration. This explains the constant effort of research on label-free detection methods. Onedimensional nanostructures, such as silicon nanowires, have emerged as good candidates for ultra-sensitive electrical detection of biological species. A silicon nanowire can operate as the channel of a field-effect transistor whose conductance is modulated by the change of charge of its surface due to the binding of biological species. A top-down fabrication process of silicon nanowire field effect transistors was developed on SOI and the influence of several physico-chemical parameters such as environmental electrostatic charges, light, buffer salinity and flow rate was evaluated. A change of the conductance of the Si nanowire according to the pH of the solution was demonstrated. Si nanowires were also tested as biosensors and allowed us to a better understanding of the involved phenomena. Complementary measurements are currently under progress.

Date Published: 5 May 2010
PDF: 10 pages
Proc. SPIE 7679, Micro- and Nanotechnology Sensors, Systems, and Applications II, 76792M (5 May 2010); doi: 10.1117/12.855451

Published in SPIE Proceedings Vol. 7679:
Micro- and Nanotechnology Sensors, Systems, and Applications II
Thomas George; M. Saif Islam; Achyut Kumar Dutta, Editor(s)