| 摘要 |
A sensor system for detecting a chemical or biological species includes a sensing element and a bias and measurement circuit. The sensing element includes nanochannels, each having an outer surface functionalized to chemically interact with the species to create a corresponding surface potential, and each having a sufficiently small cross section to exhibit a shift of a differential conductance characteristic into a negative bias operating region by a shift amount dependent on the surface potential. The bias and measurement circuit applies a bias voltage across two ends of the nanochannels sufficiently negative to achieve a desired dependence of the differential conductance on the surface potential, wherein the dependence has a steeply sloped region of high amplification substantially greater than a reference amplification at a zero-bias condition, thus achieving relatively high signal-to-noise ratio. The bias and measurement circuit converts the measured differential conductance into a signal indicative of presence or activity of the species of interest. |
