The influences of temperature, humidity, and O2 on electrical properties of graphene FETs

• Published in: Sensors and actuators. B, Chemical Vol. 285; pp. 116 - 122
• Main Authors: Hayasaka, Takeshi, Kubota, Yoshihiro, Liu, Yumeng, Lin, Liwei
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.04.2019; Elsevier Science Ltd
• Subjects: Ambient air; Chemisorption; Electric potential; Electrical properties; Empirical analysis; Field effect transistors; Gas sensor; Gas sensors; Gases; Graphene; Graphene field effect transistor; Humidity; Majority carriers; Organic chemistry; Oxygen; Semiconductor devices; Sensitivity; Sensors; Temperature; Temperature; Oxygen; Graphene field effect transistor; Gas sensor; Ambient air; Humidity
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.01.037

•The electrical properties of GFET can be drastically changed due to the influence of the ambient air and the gate voltages.•The physisorption and chemisorption models well explain the influences of humidity and O2 under different temperatures.•For both humidity and O2, GFET tends to be more sensitive in the electron regime compared with the hole regime. The influences of temperature, humidity, and O2 to the gas sensing characteristics of graphene field effect transistors (FETs) have been studied as these environmental factors are often encountered in practical gas sensing applications. Both empirical results and theoretical analyses are characterized for heated graphene FET gas sensors from room temperature to 100 °C under a wide range of applied gate voltages. It is found that at a constant applied gate voltage of −20 V with respect to the gate voltage at the neutrality point, the sensitivity of the device to humidity decreases; while the sensitivity to O2 decreases first, and increases afterwards as the operation temperature increases. These phenomena are explained by using the physisorption and chemisorption models between gases and the graphene surface. Furthermore, devices operate in the hole regime (the majority carrier is hole in the prototype devices) result in lower sensitivity to humidity and O2 as compared to those results of gas sensors operating in the electron regime due to the p-type doping effects of moisture and O2. As such, this work provides good foundations for graphene-based FET gas sensors in practical application environments under the influences of ambient air, temperature, and humidity.