Detection sensor comprising a selective high-electron-mobility transistor for detecting a gaseous or liquid component
A method and a sensor for detecting or measuring at least one specific component among a plurality of components present in a gaseous or liquid mixture by a sensor having at least one capturing cell with a high-electron mobility transistor including a source and a drain with a grid inserted between the source and the drain, a voltage being applied between the source and the drain, and a current intensity in the capturing cell being recorded. The voltage between the source and the drain is controlled, which varies the intensity of the current, the voltage being controlled according to a voltage model predetermined by experience in order to provide a profile with an intensity which is characteristic of said at least one specific component.
1. A method of detecting or measuring at least one specific component from among several components present in a gaseous or liquid mixture by means of a sensor comprising at least one collection cell having a high-electron-mobility transistor comprising a source and a drain with a gate inserted between source and drain, comprising: a drain-to-source voltage being applied; a current intensity (Imeas) in the collection cell being recorded; the source-to-drain voltage is driven; and varying the current intensity (Imeas), the voltage being driven for different voltages according to a voltage model predetermined by experiment in order to deliver a profile with an intensity which is characteristic of said at least one specific component.
2. The method according to claim 1 , wherein the profile with an intensity which is characteristic of said at least one specific component has an inversion of sign of the current intensity (Imeas) in the sensor.
3. The method according to claim 1 , wherein a same transistor of the sensor is consecutively subject to different predetermined models dedicated to different specific components.
4. The method according to claim 1 , wherein the predetermined voltage model is on a frequency voltage scale.
5. The method according to claim 1 , wherein the components detected or measured are taken, individually or in combination, from among nitrogen monoxide, nitrogen dioxide, ammonia, carbon monoxide, carbon dioxide and oxygen, these components being contained in the gases evacuated by means of an exhaust line of a motor vehicle.
6. The method for cleaning a sensor comprising at least one collection cell having a high-electron-mobility transistor comprising a source and a drain with a gate inserted between the source and the drain, the sensor operating according to a method for detecting or measuring at least one component specific to several components present in a gaseous or liquid mixture, according to claim 1 , wherein a polarization voltage is applied between at least two of the elements between the source, the drain and the gate or by an electrode inserted successively between two of the elements from among the source, the drain and the gate, the polarization voltage or the voltage of the electrode being predetermined in order to release the ions of said at least one specific component retained on the gate of the sensor.
7. A sensor for detecting or measuring at least one specific component from among several components present in a gaseous or liquid mixture, the sensor comprising: at least one collection cell having a high-electron-mobility transistor comprising a source and a drain with a gate inserted between the source and the drain; the sensor comprising a microprocessor with means for applying a voltage between the source and the drain; means for monitoring the current intensity (Imeas) in the collection cell; the microprocessor is equipped with voltage drive means according to a voltage model for different voltages saved by storage means; means for recording the current intensity (Imeas) during application of the voltage model; and means for recognizing an intensity profile characteristic of said at least one specific component saved by the storage means.
8. The sensor according to claim 7 , further comprising means for imposing a regeneration voltage between at least two of the elements from among the source, the drain and the gate or an electrode in the shape of successive slots extending successively between two of the elements from among the source, the drain and the gate and means for imposing a regeneration voltage to the electrode, the regeneration voltage being sufficient to regenerate the sensor by releasing ions of said at least one specific component retained by the sensor.
9. An assembly of at least two detection or measuring sensors, each sensor detecting a respective specific component present in a gaseous or liquid mixture, said at least two sensors are according to claim 7 , each of said at least two sensors having a stored voltage drive model and a stored intensity profile which is characteristic of said at least one specific component, a selective detection of a respective component being made by each of said at least two sensors.
10. An exhaust line of an internal combustion engine of a motor vehicle, further comprising at least one sensor according to claim 7 , or at least an assembly of at least two detection or measurement sensors, the gaseous or liquid mixture being formed by exhaust gases passing through the exhaust line and said at least one specific component or said at least two specific components being respectively one or more pollutants contained in the exhaust gas.