Humidity sensors based on QCM (quartz crystal microbalance) have been developed using an anodized alumina thin‐film as a sensing material. An aluminum thin‐film is deposited on a silver‐coated quartz crystal by electron beam deposition and is anodized in an acid solution. The resultant alumina film is porous. The resonant frequency gradually decreases from 5% to 94% relative humidity (RH) and steeply changes near 100% RH. This result shows that the sensor can be used as a dew‐point sensor as well as a humidity sensor. The response times to the humidity changes from 27% to 59% RH and from 59% to 27% RH are less than 5 s. The sensor shows reversible response to some gases such as ethanol, toluene, and acetone vapors in addition to airborne particles such as pollen.

中文翻译：

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使用阳极氧化铝膜开发QCM湿度传感器

基于QCM（石英晶体微天平）的湿度传感器是使用阳极氧化铝薄膜作为传感材料开发的。通过电子束沉积将铝薄膜沉积在镀银的石英晶体上，并在酸性溶液中进行阳极氧化。所得的氧化铝膜是多孔的。谐振频率从5％（相对湿度）逐渐降低到94％，并在100％RH附近急剧变化。该结果表明该传感器既可以用作露点传感器，也可以用作湿度传感器。对湿度从27％到59％RH和从59％到27％RH的响应时间小于5 s。该传感器除了对空气中的颗粒（如花粉）外，还显示出对某些气体（如乙醇，甲苯和丙酮蒸气）的可逆响应。