Performance Analysis And The Structural Design Of New Gas Sensor With 3D-Sensitivity Effect

With the development of science and technology, gas sensor is developing rapidly in recent years. Now, it has been widely used in the environment, industry, agriculture, national defense, and the daily lives of people in various fields. However, the gas sensors have some disadvantages to overcome, such as the low sensitivity, shortage stability, poor selectivity, catalyst poisoning, short life time and long response time, which caused a big limit in the development of the gas sensor and its application. To shorten the response time of gas sensor, the optimization structure design of the traditional gas sensor is proposed.Firstly, the paper elaborates on the principle and classification of gas sensor. Based on MEMS technology, two novel gas sensor structure models are presented by citing the concept of discrete array. The sensitive part of these two types of the model is the array which is composed of many tiny half-cylinders and multiple tiny cuboids respectively. And the discrete solid arrays made the gas sensor have the three-dimensional sensitive characteristic. The response theoretical of the sensitive arrays is analyzed, according to the response theory of diffusion model, and the response time performance of both new structure models are analyzed and compared.The analysis results show that the response time performance of the discrete sensitive arrays device is superior to that of the sensor with the planar sensitive structure. In the discrete half-cylinder array device structure, the response time of the sensor is proportionate to the distance of the tow half-cylinders. When the semi-cylinder diameter and groove span have the same numerical value, the device response time is 64% of traditional sensor with the planar sensitive structure. The response time of new structure sensor get the minimum value, 40% of the traditional structure, when the distance of the two adjacent semi-cylinders is cut to zero. In the discrete cuboids array device structure, the response time of the sensor is 25% of the traditional device while the width of rectangular is equal to the thickness of planar sensitivity film. As the width of cuboids and height of the half-cylinder have the same value, the response time performance of gas sensor with the discrete cuboids array is better than that of the device with the discrete half-cylinder array structure. For the sensors with the planar or the discrete half-cylinder array film, the response time varies directly with the thickness of sensitive film.