基于随机共振的纳米碳管气体传感器的研究

基于气体电晕放电原理,利用纳米碳管独特的物理结构和尖端发射效应,提出了一种新型的纳米碳管离子型气体传感器.采用阳极氧化铝模板法生长的定向纳米碳管阵列所构成的传感器,纳米碳管和电极是一体的,简化了器件结构和工艺.在外加直流电压激励下,纳米碳管顶部形成很强的非均匀电场,在电压相对低的情况下能很容易地电离气体,根据气体的击穿电压和放电电流来实现对单一气体和确定性混合气体的检测.为了提高检测混合气体的灵敏度,创新地在检测回路中引入随机共振发生装置,有效地提高了混合气体浓度检测的范围.实验中还分析了温度、湿度对传感器的影响,对该传感器的性能也作了评价.实验结果表明该传感器具有选择性好、体积小、响应时间快、灵敏度高、稳定性好,室温操作等优点,而且实现方便,操作简单,有较大的实用价值.

Study of carbon nanotubes gas sensor based on stochastic resonance

A novel gas ionization sensor based on corona discharge using carbon nanotubes (CNTs) was proposed. The sensor utilized unique physical structure and the field emission effect of CNTs. Due to adopting the method of anodic aluminum oxide (AAO) template to grow aligned CNTs, the electrode and CNTs were integrated, so the gas sensor simplified its structure and processing technics. As controlled DC voltage was applied to the CNTs electrode, the sharp tips of CNTs generated high electric fields, so it was easy to produce corona discharge at low voltages. As different gases have their unique breakdown voltage and discharge current, it is possible to identify one gas or certain mixture gases. In order to improve the sensitivity of the sensor, the device of generating stochastic resonance was used in the measuring circuit firstly, and the range of detecting concentration was increased greatly. The influences of temperature and humidity were discussed, and the performance of the sensor was also evaluated. Experimental results show that the CNTs gas sensor has the merits of small size, fast response, good sensitivity and selectivity. It is very convenient to be operated at room temperature and feasible in gas detection.