Research On AlN Ceramic Microplate NO₂ Gas Sensor And Its Detection System

NO₂ gas is not only one of the most important sources of environmental pollution.And it is also one of the most important test gases for hazardous chemicals safety testing.It is extremely damaging to the human body.Even a short period of exposure leads to a series of symptoms,which are of particular importance for its safe storage and transport problems and its effective and accurate detection.In view of the above problems,based on the research of existing silicon-based sensors and ceramic micro-hotplates,this paper studies and designs an AlN ceramic micro-hot plate NO₂ gas sensor.The sensor was prepared by magnetron sputtering technology,flexible mechanical stripping process and laser etching process.The sensor has a planar size of 3.2×2.0 mm and a substrate thickness of0.2 mm.Four thermal isolation holes In order to achieve the purpose of reducing the thermal gradient distribution in the heating zone and increasing the temperature efficiency.Using ANSYS finite element thermal simulation tool for thermal structural simulation analysis and thermal response test analysis to verify the rationality of thermal isolation structure design.In order to explore the best working state of the micro-hot plate NO₂ gas sensor prepared,the gas sensitivity test under different heating power consumption was performed on the sensor in the range of 150-300 m W.The comparative analysis of the obtained data shows that the sensor has the best performance when the heating power is 150-200 m W,the response rate is less than 60 s and the recovery time is about 100 s,which can realize the good detection function of NO₂ gas with the concentration of 5ppm-100 ppm.The heating power consumption of the selected sensor is 200 m W,and the NO₂ gas detection system is established based on this research.The system can be divided into two major parts of hardware and software.The core processor uses STM32 processor,while using Keil development and design of the test equipment driver,the system of communication for Zig Bee wireless data transmission mode,the host computer interface using VS software development platform for MFC design,and ultimately achieve real-time data Display,storage and alarm functions.Finally,the subject of this paper systematically tests the NO₂ gas detection system.The test results show that the NO₂ gas detection system can realize the real-time detection of NO₂ gas in the concentration range of 5-100 ppm and has a great development in the safety detection of hazardous chemicals Potential and application prospects.