Fabrication Of Nano Oxide Semiconductor Sensor Devices And Gas Sensitive Test Performance

Semiconductor-type gas sensors are important components for miniaturization,portability and high integration.In this paper,gold-loaded tungsten trioxide nanosheet materials and gold-loaded tin dioxide nanosphere materials were prepared by a relatively simple hydrothermal method and combined with MEMS microthermal plates to fabricate gas sensors and perform gas-sensitive performance tests.The experimental results show that the optimal operating temperature of the gold-loaded tungsten trioxide hydrogen sensor is 300 ℃,with a sensitivity of up to about 8,a gas-sensitive response time of 7.29 seconds and a recovery time of 10.98 seconds at a hydrogen concentration of 50 ppm,and the sensor performs well in terms of repeatability and reliability.In addition,the gas sensitivity test results of the gold load carbon monoxide sensor show that its optimal operating temperature is 250 ℃,the sensitivity to 50 ppm gas up to about 3.5,gas response time of 11.7 seconds,recovery time of 16.2 seconds,in the stability test,the sensor shows a gradual decline.The reasons for the poor stability of the carbon monoxide gas sensor and the gradual decline in response performance are mainly summarized in the following two points:(1)aging of the detection material: during a long period of use,the detection material in the sensor may deteriorate due to oxidation,damage and other reasons,thus affecting the response of the sensor.(2)the impact of surface adsorption layer: sensors in the detection process,there will likely be some adsorption layer,such as water molecules,etc.,these adsorption layers will gradually accumulate in the process of long-term use,affecting the response of the sensor.To enhance the selectivity of the sensor,a sensor array with pure tin dioxide nanospheres,gold-loaded tin dioxide nanospheres,and gold-loaded tungsten trioxide nanosheets as components was prepared in this paper.The gas response of single gas of hydrogen and carbon monoxide as well as the gas mixture of both were measured by this array,respectively,and the measured data were downscaled by combining the principal component analysis(PCA)technique to obtain the corresponding gas distribution maps.The results show that the gas distribution of the gas mixture overlaps with the distribution region of the single carbon monoxide gas and shows an overall trend toward the hydrogen distribution region,which indicates that the sensor array can greatly improve the discrimination ability of the semiconductor-type sensor for the gas.In summary,the results of this paper show that the gold-loaded tungsten trioxide hydrogen sensor and the gold-loaded tin dioxide carbon monoxide sensor exhibit good hydrogen and carbon monoxide gas detection performance at the optimal operating temperature,while the use of sensor arrays combined with principal component analysis techniques can improve the sensor’s ability to screen mixed gases and solve the cross-response problem that commonly exists in semiconductor-type gas sensors,which has great promise in the subsequent improvement of semiconductor gas sensors.