SWCNT气体传感器的NO2气敏特性

Single-walled Carbon Nanotube-based Gas Sensors for NO2 Detection

为了提高NO2气体检测的灵敏度和速度，以单壁碳纳米管（SWCNT）为装配介质，采用介电电泳方法获得单壁碳纳米管场效应晶体管（SWCNT—FET）作为气体传感器检测装置，通过原子力显微镜（AFM）和扫描电子显微镜（SEM）表征，结果显示，利用介电电泳方法能够成功地把SWCNTs装配到芯片的源漏两极间；通入NO2气体前后电特性变化情况的测试结果表明，选择接入电场频率为2MHz，峰峰值电压10V，介电电泳持续时间10s时，制备出SWCNT—FET成功率高，通入NO2气体后的电导率增加三个数量级。利用紫外光持续照射10min，SWCNT上的气体分子解附，使气体传感器可重复利用。

Single-walled carbon nanotubes have been prepared to improve the sensitivity and the speediness of NO2 de- tection. SWCNT field effect transistor（SWCNT-FET） geometry as a gas sensor detection device was obtained by using di- eleetrophoretieal. Atom force microscopy （AFM） and scanning electron microscopy （SEM） images revealed that SWCNTs were assembled between the microeleetrodes of field effect transistor. SWCNTs were affected by the eleetrophoretic force which was carried out by the related theoretical analysis in a nonuniform electric field. The electrical performance of NO2 gas sensor with SWCNT-FETs structure was tested before and after NO2 at room temperature. Experimental results showed that the efficient assembly of SWCNTs was obtained when the applied alternating current voltage has a frequency of 2MHz, SWCNTs FET with different DEP duration of 10s, and amplitude of 10V. SWCNTs-based gas sensor had high sensitivity to NO2, and the electrical conductance of NO2 gas sensor reduced three orders of magnitude. SWCNTs surface gas molecules were washed out by means of ultraviolet ray irradiation in 10 minutes, and NO2 gas sensor could be duplicated.