Fabrication of Micro Formaldehyde Gas Sensor

• Main Authors: Ping-Ru Hsieh, 謝秉儒
• Other Authors: Chia-Yen Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/83767525429677899597

碩士 === 大葉大學 === 機械工程研究所碩士班 === 94 === ABSTRACT A novel micro formaldehyde gas sensor with a sputtered NiO thin film integrated with a micro hotplate was fabricated. A microfabricated formaldehyde gas sensor is developed which uses a silica substrate with Pt micro heaters as the micro hotplate and a thin-film NiO layer as a conductivity-sensitive material. The substrate is deposited with NiO thin film as sensing elements, Pt resistors as heaters, and as interdigitated electrodes for resistance measurement. As voltages were applied to Pt heaters, temperature of micro hotplates increased. Thus, at 300oC, when formaldehyde was present in the atmosphere, it was adsorbed and as a result the electrical conductivity of NiO films was increased. The measured resistance between the interdigitated electrodes was changed. The formaldehyde gas sensor was integrated with a Pt resistor as a micro heater for the enhancement of sensitivity. A high selectivity to acetone, methanol and ethanol was alson shown in the study.