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Sensitivity Of Silicon Nanowire Biochemical Sensors
Published 2014 · Materials Science
The label-free biochemical sensors based on silicon nanowires (Si NWs) achieve selectivity to target molecules by means of a functionalization layer deposited on top of the thin dielectric that encloses the current-carrying wire. This layer consists of receptor molecules that selectively bind to the target molecules in the electrolyte. The binding process perturbs the device electrostatics and modulates the direct current (DC) or alternating current (AC) conductance (G) of the wire via surface reactions or charge displacement. The amplitude of the modulation is strongly affected by the electrolyte concentration via Debye screening effects. This chapter reviews the main definitions of sensitivity, and discusses the relation between sensitivity and noise. Next, it discusses the main physical ingredients necessary to model and simulate the sensitivity of bio-nanosensors. Finally, the chapter reports on the experimental and modeling investigation on the sensitivity of sensors composed of random nanoarrays.