Research On Humidity And Gas Sensor Based On Micro-nano Structure

Humidity sensors and gas sensors play important roles in the fields of environmental detection,aerospace defense,health care,and so on.Micro-nano structure sensors have attracted wide attention due to their excellent characteristics,such as tunability,small size,high manufacturing efficiency and low cost.In this paper,the humidity sensor and gas sensor based on the micro-nano structure are designed.At the same time,in view of the development trend of the intelligent,integrated and portable micro-nano sensors,a measurement and analysis system by smartphone is projected.The specific research content is as follows:1.Based on the micro-nano processing technology,a new humidity sensor with micro-nano structure is designed and manufactured.The photonic crystal template with controllable gap and size is prepared on the substrate by reactive ion etching?RIE?and controlled microflow injection.And then,titanium dioxide?Ti O₂?film is prepared by magnetron sputtering.The sensitive film is placed into different humidity environment for humidity test.At the same time,the measurement and analysis system is completed by combining the smartphone and grating.In this system,the dispersion image obtained by grating diffraction is used for gray-scale processing,and the corresponding intensity spectrum image can be obtained.The samples are put into different humidity for real-time sensitivity analysis and the system can obtain the real-time humidity value according to the dispersion image taken.Experiments prove that the high sensitivity humidity sensor can be reused.And then,the high integration measurement system is capable of measuring multiple elements,monitoring and analyzing dispersion image in real time.And it can realize data storage and viewing,which has practical application value.2.Based on the principle of Surface Plasmon Resonance?SPR?,a kind of Kretschmann"double-pass"structure intensity modulation optical film gas sensor is proposed.The Ag-Ti O₂ film is prepared on the substrate of K9 prism as the sensitive film for hydrogen sensing by magnetron sputtering method.The optimal parameters of the sensor membrane system are determined by MATLAB.When we fix the incident angle and the light source-1550nm,SPR will occur at the interface of Ag-Ti O_2.In the hydrogen sensing experiment,the"double-pass"structure is realized by the high reflection mirror,and the optical power meter is used to record the change of the reflected light intensity at different concentrations.The experimental results show that the SPR sensor with Ag-Ti O₂ film has a certain sensing performance for hydrogen.Compared with the traditional"single-pass"structure gas sensor,the"double-pass"structure gas sensor proposed in this paper has the advantages of good sensing performance,low cost and modularization of sensor elements.