Distinct detection of liquor ammonia by ZnO/SAW sensor: Study of complete sensing mechanism

ZnO/SAW sensor was reported to give distinct response towards liquor ammonia. To study the complete mechanism, ZnO thin films (40 nm) were deposited using rf sputtering in different reactive gas composition of argon and oxygen. The increase in oxygen content (30-100%) during film growth leads to decrease in the value of stress and bond energy. The individual contribution of different SAW sensing mechanisms such as mass loading, elastic effects and acousto-electric interaction, was evaluated and analyzed to understand the distinct response for liquor ammonia. It was found that mass loading seems to get affected by the presence of stress whereas elastic loading was affected by the crystallite size and bond energy (ZnO) in ZnO thin films.