| 摘要 |
A pair of electrodes are spaced apart on an electrically-insulating support surface. Disposed on the surface in a position bridging the electrodes is a sensor that exhibits a change in conductivity in response to exposure of the material to a wide variety of certain flammable and toxic gases. Overlying the sensor is a molecular sieve passivation layer composed of a porous solid material that has a pore size no larger than the molecular size of the gas to be sensed. The molecular sieve passivation layer can be incorporated onto various solid state and catalytic-type gas sensors, including metal oxide based solid-state sensors such as, for example, those of a zinc oxide base. With or without the sieve, the most salient form of zinc oxide based sensor is zinc oxide doped with gallium oxide. It is expedient to use such improved sensors as a discrete device or in a hybrid array for environmental ambient qualification as incorporated into a portable instrument.
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