Formaldehyde gas sensor based on TiO2 thin membrane integrated with nano silicon structure

• Published in: Optoelectronics letters Vol. 12; no. 4; pp. 308 - 311
• Main Author: 郑轩 明安杰 叶丽 陈凤华 孙西龙 刘卫兵 李超波 欧文 王玮冰 陈大鹏
• Format: Journal Article
• Language: English
• Published: Tianjin Tianjin University of Technology 01.07.2016
• Subjects: Lasers; MEMS工艺; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; 二氧化钛薄膜; 制作工艺; 气体传感器; 甲醛; 硅结构; 等离子体浸没离子注入; 纳米TiO2膜
• ISSN: 1673-1905; 1993-5013
• DOI: 10.1007/s11801-016-5249-5

An innovative formaldehyde gas sensor based on thin membrane type metal oxide of Ti O2 layer was designed and fabricated. This sensor under ultraviolet（UV） light emitting diode（LED） illumination exhibits a higher response to formaldehyde than that without UV illumination at low temperature. The sensitivities of the sensor under steady working condition were calculated for different gas concentrations. The sensitivity to formaldehyde of 7.14 mg/m3 is about 15.91 under UV illumination with response time of 580 s and recovery time of 500 s. The device was fabricated through micro-electro-mechanical system（MEMS） processing technology. First, plasma immersion ion implantation（PIII） was adopted to form black polysilicon, then a nanoscale TiO2 membrane with thickness of 53 nm was deposited by DC reactive magnetron sputtering to obtain the sensing layer. By such fabrication approaches, the nanoscale polysilicon presents continuous rough surface with thickness of 50 nm, which could improve the porosity of the sensing membrane. The fabrication process can be mass-produced for the MEMS process compatibility.