Sensor parameters and the new Kelvin probe technique

摘要

This paper points out the importance of one of the most important sensor parameters, i.e. the sensitivity which has been calculated for different sensors. This parameter allows both the resolution and the minimum detectable signal to be calculated once the noise measurement is estimated or determined at the experimental level. In the nanotechnology era where material science is developing so fast and new devices are coming to light, a spontaneous question is whether or not the sensitivity of the new emerging sensors is going to improve. In order to give an estimation of the performance trend, response curve, sensitivity, noise, resolution and stability of these parameters have to be taken into severe consideration. As an example we know for sure that in the case of the MOSFET utilized as a transducer in the chemical sensor context, the transconductance is decreasing with the gate length, while coating problems due to the small gate area are arising; contacts in conductivity-based nanosensors may create stability problems not at all tolerable. The idea now is to carefully consider the nanotechnology development and see if the shrink of the sensor dimensions may represent a problem. Of course, in order to keep small volumes under control, much dimensionally small compatible sensors should be developed keeping always in mind that at the end the growing problem is to get useful information from those nanovolumes for which the surface-to-volume ratio may have high values and the best sensor localization has not been identified yet.