Magnetron co-sputtering optimized aluminum-doped zinc oxide (AZO) film for high-response formaldehyde sensing

It is very important to conduct trace detection of the gas formaldehyde, a harmful gas of volatile organic compounds (VOCs) that threatens human health. In the present work, the aluminum-doped zinc oxide (AZO) films with different aluminum contents were prepared on silicon substrate by magnetron co-sputtering technology. The test results showed that when the sputtering power of ZnO was 150 W and the sputtering power of Al2O3 was 50 W, the AZO thin film sensor had the best response to formaldehyde at an operating temperature of 240 degrees C. The sensor had a good response to 100 ppb-3 ppm formaldehyde, and its response to 100 ppb formaldehyde at 240 degrees C was as high as 43%. The sensor could detect as low as 50 ppb to formaldehyde, and it also exhibited good repeatability, long-term stability, as well as good selectivity over other gases (hydrogen, carbon monoxide, ammonia, benzene, isoprene, nitrogen dioxide and acetone). Therefore, this AZO thin-film sensor is expected to be used in indoor formaldehyde monitoring. (C) 2021 Elsevier B.V. All rights reserved.