Optimized temperature-pulse sequences for the enhancement of chemically specific response patterns from micro-hotplate gas sensors

Microfabricated solid-state gas sensors have been of continuing interest because of the potential for arrays of devices with low power consumption. Devices based on a micromachined 'hotplate' offer the additional advantage of a wide operating temperature range with a rapid thermal time constant of order 1 ms. By operating the device in a temperature-programmed mode, reaction kinetics on the sensing film surface are altered, producing a time-varying response signature that is characteristic of the gas being sensed. Approaches to optimizing such temperature programs to maximize the differences in response signatures for gases of interest or to enhance the sensitivity of the device are discussed.