Increasing the Gas Response of Ozone Sensors Based on Solution-Processed InGaZnO by Tuning the Size of the Nanostructure

Abstract

This study uses acetylacetone (acac) as an additive to control the size of the nanostructure of solution-processed a-IGZO for ozone (O3) gas sensor applications. It is found that by adding acac, the gas response, response time, and recovery time of an IGZO gas sensor are highly improved. Under the optimal condition (4 wt%), the IGZO sensor shows a gas response of 19 and a response/recovery time of 80/120 s, against 5 ppm O3. Adding acac significantly increases the number of oxygen vacancies within an a-IGZO film so more electrons are available for reaction with the gas. The increased number of oxygen vacancies means that more dangling bonds are created, which activates the gas adsorption process. Moreover, the IGZO gas sensor has an excellent long-term stability showing negligible variation in gas response over 2 months. This method allows easy fabrication of a high-performance gas sensor that uses solution-processed a-IGZO as a sensing layer.