Mechanism of gas sensing in carbon nanotube field effect transistors
Mechanism of gas sensing in carbon nanotube field effect transistors
复制标题
碳纳米管场效应晶体管的气体传感机制
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Isha Dube
中科院分区：
文献类型：
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作者：
Isha Dube
Gas sensors based on carbon nanotubes in the eld e ect transistor con guration have exhibited impressive sensitivities compared to the existing technologies. However, the lack of an understanding of the gas sensing mechanism in these carbon nanotube eld e ect transistors (CNTFETs) has impeded setting-up a calibration standard and customization of these nano-sensors for speci ed gas sensing application. Calibration requires identifying fundamental transistor parameters and establishing how they vary in the presence of a gas and in uence the overall sensing behavior. This work focuses on modeling the sensing behavior of a CNTFET in the presence of oxidizing (NO2) and reducing (NH3) gases and determining how each of the transistor parameters, namely: the Schottky barrier height, Schottky barrier width and doping level of the nanotube are a ected by the presence of these gases. Earlier experiments have shown that the carbon nanotube-metal interface is responsible for the observed change in the CNTFET response. The interface consists of the metal contact and the depletion region in the carbon nanotube. A change in the metal work function will change the Schottky barrier height, whereas doping of the depletion region will a ect the Schottky barrier width and the doping level of the carbon nanotube. A theoretical model containing these parameters was systematically tted to the experimental transfer characteristics for di erent concentrations of NO2 and NH3. A direct correlation between the measured changes in the CNTFET
