【作者】 苏梅英；

【导师】 王兢；

【作者基本信息】 大连理工大学 ， 电路与系统， 2012， 博士

【摘要】 湿度测量与控制与国民经济的发展和人们生产生活密切相关,目前已在工农业生产、日常生活、气象、环保等各个领域广泛应用。在各种测量湿度的方法中,电子式的湿度传感器因其可与现代控制、显示、记录装置相连而备受关注。随着物联网在工业、环境检测及智能小区等领域的发展,对传感器的发展也有了更高要求。对湿度传感器而言,感湿性能提高（高灵敏度、快速响应时间,良好的一致性和稳定性等）以及器件的集成化、微型化成为主要发展方向。由于纳米材料具有大比表面积和电子定向传导等优点,研究纳米结构的敏感材料在促进湿度传感器的发展上具有很重要的价值。本文首先设计了湿度传感器在线测量系统。该系统可以实时采集被测湿敏元件在不同湿度、不同频率下的阻抗、幅角、电容以及损耗等电学参量。提高了实验数据的准确度,并消除了人为因素引起的测量误差。本文主要研究了以下四种纳米ZrO2湿度传感器的感湿特性：（1）CMOS工艺兼容的ZrO2薄膜湿度传感器；（2）ZrO2∶TiO2分级结构异质纳米纤维湿度传感器；（3）碱离子掺杂纳米粉体ZrO2厚膜湿度传感器；（4）Mg^（2+）掺杂纳米纤维ZrO2厚膜湿度传感器。对每一类型的湿度传感器的研究均涉及湿敏材料制备、材料表征、传感器制作、性能测试和相应理论分析五部分内容。文中利用XRD、TG、DTA/DSC和FT-IR等材料表征结果分析了湿敏材料ZrO2晶体结构及其生长机理；利用SEM、TEM等表征观察材料的形貌,并结合BET、XPS表征结果探讨湿敏材料微结构对湿度传感器性能的影响。所研究的湿度传感器的性能包括：灵敏度、湿滞、响应-恢复、温度特性等。ZrO2湿度传感器体现了灵敏度高、湿滞小、响应快、热稳定性好等特点,在解决湿度传感器灵敏度低、稳定性差等问题上提供了重要的参考价值。从介电特性、直流特性和交流特性的角度探讨了纳米ZrO2湿度传感器的感湿机理。由介电损耗特性得知,在器件感湿过程中,感湿材料中的束缚电荷通过极化的方式参与了导电。同时器件的直流特性表明参与导电的载流子还包括电子和离子两种类型。在交流复阻抗分析法中引入电化学元件CPE和Warburg元件构建等效电路,并通过复阻抗分析软件ZView进行等效电路的最佳拟合。结合器件以上三种特性,确定了低、中、高湿段何种电荷对器件的传导机制起主导作用。并多角度分析了频率、温度分别对器件阻抗和复阻抗的影响。文章同时给出了纳米ZrO2湿度传感器的吸附模型以及质子在各模型中的传输机制。更多还原

【Abstract】 Monitoring and controlling humidity have been widely used in industry, agriculture, daily life, meteorology and environmental protection which closely related to living of people and society development. Electric humidity sensors have been interested due to their connection with modern machines which can control, display and record. With the development of internet of things in industry, environment monitoring and intelligent community, higher requirement have to be needed for sensors. In view of humidity sensor, the main development views include higher humidity sensing properties (high sensitivity, rapid response time, good repeatability, long-term stability, etc.), integration and miniaturization of humidity sensors. Because of high surface area and oriented electron conduction of nanometer material, it is important to study sensitive materials with nanostructure for promoting the development of humidity sensors.A real-time test system has been developed for measuring humidity properties of humidity sensors. The testing system can be used to obtain electrical characteristics of humidity sensors at different humidity levels and measurement frequencies, such as impedance, phase angle, capacitance, dielectric loss, etc. Using the test system can improve the accuracy of experimental data and eliminates measurement errors caused by manual.Four kinds of humidity sensors based on zirconia have been mainly studied in the present dissertation, including CMOS process compatible ZrO2thin film humidity sensor, ZrO2:TiO2hierarchical hetero-nanofibers humidity sensor, alkaline doped nano-powder ZrO2thick film humidity sensor and Mg2+-doped nanofibers ZrO2thick film humidity sensor. Preparation and characterization of humidity sensing materials, fabrication and measurement of humidity sensors, and related theory on humidity sensing properties of sensor have been researched for the four kinds of humidity sensors. Crystal structure and growth mechanism of nano-ZrO2have been analyzed via using some important characterization technologies, including XRD, TG, DTA/DSC, FT-IR, etc. Morphologies of ZrO2have been characterized by SEM and TEM methods. The influences of micro structures of sensing materials on the humidity sensing properties of sensors have been discussed via BET and XPS technologies. In the present dissertation, the humidity properties of sensors include sensitivity, humidity hysteresis, response and recovery, temperature properties, and so on. High sensitivity, small hysteresis, rapid response and good thermal stability of the ZrO2humidity sensors have been exhibited, which will provide an important reference value for solving low sensitivity and poor stability issues of humidity sensors.Humidity sensing mechanisms of nano ZrO2humidity sensors have been discussed in view of dielectric properties, DC and AC characteristics. The bound charges contribute to the conduction of sensor in mean of polarization during the humidity sensing process, according to the dielectric loss properties of the sensors. And electronics and ions also play the conduction role by analyzing the DC transient characteristics of the sensors. The equivalent circuits with electrochemical elements CPE and Warburg have been created by using AC impedance method, which simulated and fitted using the complex impedance analysis software ZView perfectly. According to the afore-mentioned three characteristics of the sensors, it has been determined which kinds of charge play the major role in the conduction process of the sensor at low, medium and high humidity ranges. The influences of measurement frequency and measurement temperature on the impedances and complex impedances of the sensor have been discussed in different views.In the present dissertation, the adsorption models of the nano-ZrO2humidity sensors and the transmission mechanisms of proton among which have been also discussed.更多还原