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Title An FET-Type Gas Sensor for CO2 Detection at Room Temperature using PEI-Coated SWNT
Authors Meile Wu(Meile Wu) ; 홍윤기(Yoonki Hong) ; 장동규(Dongkyu Jang) ; Xiaoshi Jin(Xiaoshi Jin) ; 이종호(Jong-Ho Lee)
Page pp.196-202
ISSN 1598-1657
Keywords CO2 sensor ; room temperature ; FET ; SWNT ; PEI
Abstract An FET-type CO2 sensor using polyethylenimine (PEI) coated single-walled carbon nanotube (SWNT) is investigated. The sensor has a floating-gate (FG) and a control-gate (CG) formed in an interdigitated form in a horizontal direction. SWNT and PEI are sequentially printed on the platform by inkjet printing process. PEI coating reduces the I-V hysteresis of the FET platform and improves the CO2 sensing properties. Since the sensor has an FG that can store the charge, the threshold voltage of the sensor can be tuned and its calibration is possible. When sensing 2000 ppm of CO2 gas at room temperature, the DC read bias applied to CG showed very low sensitivity and significant drift characteristics. However, by applying a pulse bias, a response of ~16%, a response time of ~80 s, and a recovery time of ~200 s were obtained.