Design Strategies of Integrated Metal-Oxide Semiconductor-Based Resistive Sensor Systems for Ammonia Detection

Chemical production activities cause large amounts of ammonia to evaporate into the atmosphere, degrading air quality and even endangering public health, so monitoring ammonia in real time is significant. Traditional detection techniques, including spectrometers, chromatography, and pumping methods, are characterized by high costs, complex operation, significant delays, and limited compatibility, which obstructs the immediate identification of ammonia and the timely provision of information. Due to their distinct benefits such as compact size, affordability, quick response time, and lack of need for manual operation, resistive ammonia sensors hold significant promise for the real-time tracking of ammonia emissions in chemical manufacturing processes. In recent years, sensors utilizing metal-oxide semiconductor (MOS) nanomaterials have become a popular area of research due to their high sensitivity, strong stability, and acceptable response and recovery times. However, the interface circuits of existing MOS gas sensors mainly focus on sensor configuration and data acquisition. These interface circuits lack the functions of array timing control and data processing; gas detection and identification cannot be realized directly by them, which reduces the system integration and increases the application complexity. This paper begins by examining key design strategies for MOS-based resistive sensors aimed at enhancing ammonia sensing capabilities, offering researchers a foundation for their work in creating high-performance ammonia sensors. Based on this, a complete measuring system and a programmable interface circuit for an MOS gas sensor are introduced, which can integrate sensor configuration, signal acquisition, data processing, and output of recognition results. Finally, the current challenges and future opportunities of MOS-based resistive ammonia sensor systems are presented. The purpose of this review is to offer researchers suggestions for creating high-performance MOS-based resistive ammonia sensor systems and to promote the use of these sensors in upcoming chemical manufacturing processes.