HIGH-TEMPERATURE TOLERANT DIAMOND-BASED MICROELECTRONIC OXYGEN GAS SENSOR

A new diamond-based microelectronic gas sensor catalyst/adsorptive-oxi de/insulator/semiconductor, CAIS device) has been developed for the de tection of oxygen and CO gases. The gas sensing performance, detection mechanisms and activation energy analysis of the sensor for oxygen an d CO gases have been analyzed. The gas sensitivity of the sensor is hi gh, repeatable, and reproducible. The response time is in seconds to a small concentration of oxygen and CO gases. The gas detection mechani sm of the new sensor is attributed to the change in the oxygen vacanci es of the SnOx layer upon oxygen and CO exposure, causing several mill iamperes of change in device current. The adsorption activation energy analysis of the sensor reveals small values, 2.8 +/- 0.1 kcal mol(-1) and 1.1 +/- 0.1 kcal mol(-1) for oxygen and CO gases, respectively, c onfirming the high sensitivity and fast response of this new sensor. T he diamond-based CAIS gas sensor could be applied for the detection of oxidizing and reducing gases over a higher and wider temperature rang e than is currently possible. (C) 1998 Elsevier Science S.A. All right s reserved.