Ultrasensitive nanosensors based on electronic effects in nanoscale structures
in: SPIE Proceedings (2011)
Charge carrier distribution changes in solid substrates induced by the presence of biomolecules have the potential as sensoric principle. For a high surface-to-bulk ratio as in the case of nanostructures, this effect can be used for highly sensitive bioanalytics. Plasmonic nanosensors represent one possible implementation: The resonance wavelength of the conductive electron oscillation under light irradiation is changed upon molecular binding at the structure surface. This change can be detected by spectroscopic means, even on a single nanoparticle level using microspectroscopy. Other examples are nanowires in electrodes gaps, either by metal nanoparticles arranged in a chain-like geometry or by rod-like semiconductor nanowires directly bridging the gap. Molecules binding at the surface will lead to changes in the electrical conductivity which can be easily converted into an electrical readout. The various geometries will be discussed and their sensoric potential for an electrical detection demonstrated.