Enhancement of acetylene gas sensing properties for a ZnO-based gas sensor produced by plasma immersion ion implantation and deposition

Zinc oxide (ZnO) based gas sensors with sensitivities reaching 90% and time responses as low as two seconds for acetylene sensing (1 vol%), were produced by means of plasma immersion ion implantation and deposition (PIII &D). In the process, after the generation of an argon glow discharge, metallic zinc is vaporized, partially ionized and implanted/deposited into/onto silicon substrates without the aid of catalysts or buffer layers. Calcination is performed after treatment in atmospheric pressure at 500 degrees C, for 10 h, leading to the achievement of polycrystalline ZnO nanostructures. The resistance change of the sensor was monitored by varying the respective working temperature from 140 degrees C up to 280 degrees C for three different acetylene concentrations (1, 2, 3 vol%). Besides the high sensitivity and the fast response time, the recovery time was also measured and the repeatability of the sensor was tested by feeding and cutting the working gas supply into the measuring system at regular time intervals.