Catalytic gas sensor with single-crystalline silicon heater

A single-crystalline silicon heater used in a catalytic sensor of the pellistor type qualitatively changes the pattern of active gas detection, which is related to a nonlinearity of the current-voltage (I-U) characteristic. The shift of the I-U curve toward lower values of the heater current allows both positive and negative components in the sensor response to be separated as determined by varying the bias voltage at a fixed value of the heater current. Under the action of carbon monoxide, the positive component of the sensor response exhibits a clearly pronounced maximum at a heater current of 28 mA and the height of this peak is proportional to CO concentration in a range of 0.5–2.0 vol %.