
554 Nanosensors: Physical, Chemical, and Biological
current owing between two electrodes. The device, therefore, acts as a
chemically sensitive FET, with adsorbed charged species acting as the
“gate.” NW sensors can be very sensitive because a signicant fraction of
the carriers in the NW can be depleted so that a small number of carriers
induced by the analyte changes the conductance signicantly. What is the
problem in interfacing NWs with circuitry? Using the NWs requires that they
be connected to electrodes that can interface with other circuitry. The size
mismatch between the nanoscale wires and conventional electrodes has
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