Sensitivity and selectivity of chemoresistor type gas sensors
AssigneesAlpha M.O.S., Centre National de la Recherche Scientifique (CNRS)
InventorsChang Hyun Shim, Francois Loubet, Alain Gaudon, Philippe Menini, Franck Benhamouda, Jean Christophe Mifsud
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Abstract
The sensitivity and/or selectivity of a chemoresistor type gas sensor is enhanced by measuring the response of the sensing material to a gas sample while the sensing material is subjected to illumination using specially-tailored pulses of ultraviolet radiation. For a given target gas to be detected there is an optimal duration of the UV pulses to achieve peak sensitivity of the sensing material.
Claims18
A chemoresistor gas sensor comprising:
- a gas-sensitive layer;
- an ultraviolet light source configured to expose the gas-sensitive layer to pulses of ultraviolet light;
- a setting unit that controls a duty ratio or duration of the pulses of the ultraviolet light applied by the ultraviolet light source in dependence on a target gas species to be adsorbed on the gas-sensitive layer;
- and
- a control module that sets, by the setting unit, the duty ratio or duration of the pulses of the ultraviolet applied in the gas sensor to different values for discrimination of respective different target gas species.
A method of operating a chemoresistor gas sensor comprising a gas-sensitive layer, the method comprising the step of
- applying pulses of ultraviolet light to the gas-sensitive layer, wherein a duty ratio or duration of the pulses of ultraviolet light is set dependent on a target gas species to be adsorbed on the gas-sensitive layer;
- wherein the step of applying pulses of ultraviolet light to the gas-sensitive layer comprises setting the duration or duty cycle of applied ultraviolet pulses to different values for discrimination of respective different target gas species.
A chemoresistor gas sensor comprising:
- an array of sensing elements, each of the sensing elements comprising a gas-sensing layer and measurement electrodes provided in contact with the gas-sensing layer;
- plural sources of ultraviolet light operable to expose selected gas-sensing layers of the array of sensing elements to ultraviolet light;
- and
- a control module that controls the plural sources of ultraviolet light according to a measurement protocol that comprises applying ultraviolet pulses having different duty ratios to different sensing elements of said array at substantially the same time.
A chemoresistor gas sensor comprising:
- a gas-sensing layer provided on an insulating layer,
- measurement electrodes provided in contact with the sensing layer;
- and
- a source of ultraviolet light operable to expose the sensing layer to ultraviolet light;
- characterised in that the gas sensor comprises an analysis unit that determines the transient response of the sensing layer at onset of application of ultraviolet light by analysis of measurements taken via the measurement electrodes.
A method of operating a chemoresistor type gas sensor comprising a gas-sensing layer provided on an insulating layer, measurement electrodes provided in contact with the sensing layer, and a source of ultraviolet light operable to expose the sensing layer to ultraviolet light, the method comprising the steps of:
- exposing the sensing layer to ultraviolet light, and
- analyzing measurements taken via the measurement electrodes to determine the transient response of the sensing layer at onset of application of ultraviolet light.
Dependencies are inferred from the claim text.