镀有SiO_2-WO_3纳米复合薄膜LPFG气体传感特性研究

The Research of Gas Sensitivity Characteristic of LPFG Doped by SiO_2-WO_3 Nano-Composition Thin Film

以钨粉和正硅酸乙酯为原料,采用溶胶-凝胶工艺和浸渍提拉镀膜方法,在玻璃衬底上制备出了具有气敏传感特性的SiO2-WO3纳米复合薄膜.采用原子力显微镜和X射线衍射仪表征了薄膜样品的表面形貌和物相结构.实验结果表明:掺杂SiO2使WO3薄膜中的颗粒尺寸减小,空隙率提高,比表面积增大.将SiO2-WO3复合薄膜镀于长周期光纤光栅上(LPFG),在室温条件下,将LPFG置于体积分数为2%的NO气体中,LPFG谐振峰红移了4.77 nm,损耗由-9.93 dB变为-8.53 dB,相应的气体传感灵敏度达到3%,元件响应时间10 s,恢复时间20 s.

The SiO2-WO3 nano-composition thin film with the gas sensitivity was prepared on glass substrate by sol-gel technical process using the tungsten powder and the tetraethoxysilanes as precursor. The crystal structure and surface topograph of the thin film were characterized by X-ray diffraction （XRD） and atomic force microscopy （AFM） . The experimental results show that, doping SiO2 causes the reduction of the crystalline grain size of the WO3 thin film , the increasing of the duty porosity and the surface area. The SiO2-WO3 nano-composition thin film was prepared on the LPFG. When the LPFG was deposited to the NO gas of volume fraction 2% under the room temperature , the red shift of LPFG resonance peak is 4. 77 nm , while the transmission of LPFG resonance peak is from -9.93 dB to -8. 53 dB and the relative gas sensor sensitivity achieves 3 % . The response time of the sensor is tres=3. 5 S and the recovery time is trey = 1. 5 S.