以多壁碳纳米管(multi-walledcarbonnanotubes,MWCNTs)和α-六噻吩(α-sexithiophene,α-6T)双层膜作为有源层,二氧化硅(SiO2)为绝缘层,钛/金(Ti/Au)作为电极,制备了沟道宽长比为640的有机薄膜晶体管(organicthin-filmtransistors,OTFT)气体传感器.测试了该传感器对痕量二氧化氮(NO2)气体的实时响应特性,并分析了NO2 气体对OTFT传感器阈值电压、载流子迁移率等多参数的影响.研究结果表明,基于MWCNTs/α-6T 的OTFT器件有较好的电学特性,载流子迁移率为3.0×10-2cm2/V·s;OTFT传感器对NO2 气体具有较高的响应率,响应和恢复时间短,能检测(0.2~1)×10-6 的痕量NO2 气体,且具有良好的重复性;同时可以利用阈值电压和载流子迁移率等多参数来表征响应结果.形貌分析结果表明双层敏感膜的特殊形貌有利于提高器件的气敏性能.
Abstract: The multi walled carbon nanotubes (MW(NTs) and α-sexithiophene (α-6T) bilayer were taken as the active layer, and silicon dioxide (SiO2) was used as the insulating layer. Titanium..'aurum (Ti..'Au) were made as the electrode for the prepared OTFT gas sensor,of which the ratio of channel width to length was 640. The real time response characteristics of the sensor exposed to nitrogen dioxide (NO2) were tested, and the effect of NOe on the multi parameters of the OTFT sensor, such as threshold w)ltage and carrier mobility, was ana lyzed. The results showed that, the OTFT device based on MWCNTs/α 6T bilayer performed better electrical properties, and the carrier mobility reached 3. 0 × 1 0-2 cm2/V · s. The OTFT gas sensor showed the high re sponse when exposed to NO2 , and the time of response and recovery were short. The trace (0.2-1 )×1 0 -6 NO2 were detected and the sensor also had the good repeatability. It was feasible to take the multi parameters to present the gas response results. Morphology analysis showed that the special feature of the bilayer was helpful for improving the gas sensitivity.