S Baumgartner et al 2011 Nanotechnology 22 425503 doi:10.1088/0957-4484/22/42/425503
S Baumgartner1, M Vasicek1, A Bulyha1 and C Heitzinger1,2
Show affiliationsIn order to facilitate the rational design and the characterization of nanowire field-effect sensors, we have developed a model based on self-consistent charge-transport equations combined with interface conditions for the description of the biofunctionalized surface layer at the semiconductor/electrolyte interface. Crucial processes at the interface, such as the screening of the partial charges of the DNA strands and the influence of the angle of the DNA strands with respect to the nanowire, are computed by a Metropolis Monte Carlo algorithm for charged molecules at interfaces. In order to investigate the sensing mechanism of the device, we have computed the current–voltage characteristics, the electrostatic potential and the concentrations of electrons and holes. Very good agreement with measurements has been found and optimal device parameters have been identified. Our approach provides the capability to study the device sensitivity, which is of fundamental importance for reliable sensing.
87.85.Qr Nanotechnologies-design
87.15.B- Structure of biomolecules
87.80.-y Biophysical techniques (research methods)
02.70.Uu Applications of Monte Carlo methods
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
Issue 42 (21 October 2011)
Received 13 July 2011, in final form 1 September 2011
Published 26 September 2011
S Baumgartner et al 2011 Nanotechnology 22 425503
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