Pan Mingqiang, Sheng Jun, Liu Jizhu, Shi Zeming, Jiu Lei
School of Mechanical and Electric Engineering, Soochow University, Suzhou 215123, China.
Jiangsu Provincial Key Labor Atory of Advanced Robotics, Soochow University, Suzhou 215123, China.
Sensors (Basel). 2020 Mar 20;20(6):1736. doi: 10.3390/s20061736.
Humidity detection range is an important indicator for measuring the performance of humidity sensors, but semiconductor humidity sensors often face the problems of narrow detection ranges and insufficient detection sensitivities. In this paper, a magnesium oxide (MgO) humidity sensor based on micro-arc oxidation (MAO) technology was designed to solve these problems by simultaneously using impedance and capacitance as the response signals, as well as by normalizing the output of the two signals. The experimental results showed that the average output of the micro-arc MgO ceramic film, with impedance as the response signal, could reach 150 in the low relative humidity(RH) range (11.3-67% RH), which was much higher than its sensitivity in the high humidity range (< 1), and the film showed fast response (13 s) and recovery (61 s). Under high humidity conditions (67-97.3% RH), with capacitance as the response signal, the output of the micro-arc MgO was as high as 120. Therefore, the micro-arc MgO humidity sensor with impedance, and the sensor with capacitance as the response signal, demonstrated good stability in low humidity and in high humidity environments, respectively, indicating that the method of selecting appropriate response signals for different humidity environments can be applied to extend the humidity detection range of sensing material, and to improve the humidity detection capability of a sensor.
湿度检测范围是衡量湿度传感器性能的一个重要指标，但半导体湿度传感器常常面临检测范围窄和检测灵敏度不足的问题。本文设计了一种基于微弧氧化（MAO）技术的氧化镁（MgO）湿度传感器，通过同时使用阻抗和电容作为响应信号，并对这两个信号的输出进行归一化处理来解决这些问题。实验结果表明，以阻抗为响应信号时，微弧氧化镁陶瓷膜在低相对湿度（RH）范围（11.3 - 67%RH）内的平均输出可达150，远高于其在高湿度范围（<1）时的灵敏度，且该膜响应迅速（13秒）、恢复快（61秒）。在高湿度条件下（67 - 97.3%RH），以电容为响应信号时，微弧氧化镁的输出高达120。因此，以阻抗为响应信号的微弧氧化镁湿度传感器和以电容为响应信号的传感器分别在低湿度和高湿度环境中表现出良好的稳定性，这表明针对不同湿度环境选择合适响应信号的方法可用于扩展传感材料的湿度检测范围，并提高传感器的湿度检测能力。
