Patent ID: 6077712
Filing Date: 2000-06-20
Classification: G01N,Y10T

Abstract:
A semiconductor chemical sensor for detecting a chemical species in a gas, comprising:a) a detector element comprising:i) an inlet surface; andii) a porous layer comprised of an organic semiconductor material on which the chemical species is adsorbed, the porous layer having a depletion region;b) a power source electrically connected to the detector element to produce a bias voltage in the detector element such that the chemical species percolates through the porous layer and into the depletion region under the bias voltage, thereby changing the capacitance of the detector element;c) a light source disposed to irradiate the gas with light before the gas enters the detector element at the inlet surface, the light source emits at least one light wavelength effective to change the chemical properties of the chemical species so as to enhance the adsorption selectivity of the organic semiconductor material with respect to the chemical, species; andd) means for determining the presence of the chemical species in the gas based on the change in capacitance in the depletion region.