基于Si-NPA的BaTiO3薄膜的电容湿敏性能研究

采用溶胶-凝胶和旋涂技术制备了基于Si-NPA的BaTiO3薄膜(BaTiO3/Si-NPA).场发射扫描电镜和X射线衍射实验表明,钙钛矿结构BaTiO3薄膜很好地覆盖了Si-NPA表面.通过蒸镀双面梳状电极,制作了电容型BaTiO3/Si-NPA湿敏元件并对其湿敏性能进行了测试.结果表明,室温下湿敏元件在11%～95%RH范围内具有很高的灵敏度和较快的响应速度,且电容值的对数对湿度呈现出很好的线性.虽然该薄膜湿敏元件在不同湿度下均存在温度漂移,但分析表明这种漂移有可能通过电极设计或信号补偿加以解决.

Capacitive humidity sensing properties of BaTiO3 thin film spin-coated on Si-NPA substrate

BaTiO3 thin film based on Si-NPA (BaTiO3/Si-NPA) was prepared through sol-gel method and spin-coating technique. The characterization on its surface morphology and structure by field-emission scanning electron microscope and X-ray diffractometer disclosed that the surface of Si-NPA was well covered by a layer of perovskite BaTiO3 thin film. Through evaporating two-side comb-type aluminum electrodes on BaTiO3/Si-NPA, a capacitive humidity sensor was fabricated and the corresponding humidity sensing properties were tested. It was shown that in the relative humidity (RH) range of 11% - 95%RH, BaTiO3/Si-NPA sensor could exhibit high vapor sensitivity and fast response/recovery rate, and the device response curve described by capacitance logarithmic coordinate could be highly linear. Although the humidity sensor had temperature drift at different humidity levels, the analysis result indicated that the drift might be solved by the design of electrodes or signal compensation.