I-Corps: Efficient nanowire based gas sensor

这个i-Corps项目的更广泛的影响/商业潜力是开发一个传感器平台，可以监测环境中有毒气体的存在。该设备旨在用于广泛的应用，从石油和天然气行业的使用，到用作法律和秩序以及与健康相关的领域的呼气分析仪。拟议中的纳米级设备将产生相对便宜和可靠的气体传感器，可以在天然气开采地点周围使用，监测二氧化硫、甲烷、一氧化碳、氨和氢气等极少量的有毒气体。它们也可以安装在学校和医院的选定区域。医疗人员可以使用传感器来测试呼出空气的质量，以检测高水平的一氧化氮(高水平的哮喘)、高水平的硫(高水平的肝脏功能障碍)和丙酮(高水平的糖尿病患者)。I-Corps项目建议使用一维纳米线作为传感元件，工作原理是纳米线的电阻随着其表面被吸附的气体分子改变而变化。纳米线的长度为几十微米，直径在纳米范围内，具有很大的比表面积比。因此，每根纳米线上将有大量的表面位，以促进与吸附的气体分子的表面反应。该项目基于成功的实验，在这些实验中，在暴露于氨、甲醇、氯、氢和硫等气体后的几秒钟内，测量了单个纳米线的电导的显著变化。当气体分子被吸附在纳米线表面时，由于能带结构的改变而引起的纳米线沟道电导的变化主导了传感机制。预计纳米级传感器将具有高灵敏度，响应速度更快，可以在室温下工作，需要较低的工作功率。为了提高气体选择性，可以在纳米线表面添加额外的特征。安装在单个芯片上的这种纳米线阵列将产生一种高度通用的设备，可以用于监测和感应我们周围环境中的有毒气体。

The broader impact/commercial potential of this I-Corps project is the development of a sensor platform that can monitor the presence of toxic gases in the environment. The device is intended for a wide range of applications ranging from its use in the oil and gas industry to its use as breath analyzers with applications in law and order as well as in health related fields. The proposed nanoscale device will result in relatively cheap and reliable gas sensors that can be used around gas extraction sites to monitor extremely small concentrations of toxic gases like sulphur dioxide, methane, carbon-monoxide, ammonia and hydrogen. They can also be mounted in select areas in schools and hospitals. Medical personnel could use the sensor to test the quality of exhaled air to detect high levels of nitric oxide (high levels indicative of asthma), sulfur (high levels indicative of liver dysfunction) and acetone (high levels in diabetic patients).This I-Corps project proposes to use one-dimensional nanowires as sensing elements, working on the principle that the nanowire resistance changes as its surface is modified by adsorbed gas molecules. With lengths of several tens of microns and diameters in the range of nanometers, nanowires have large surface-to-volume ratio. Hence a large number of surface sites will be available on each nanowire to facilitate surface reactions with the adsorbed gas molecules. The project is based on successful experiments where significant changes in the electrical conductance of individual nanowires were measured within several seconds of exposure to gases like ammonia, methanol, chlorine, hydrogen, and sulfur. The sensing mechanism is dominated by changes in the nanowire channel conductance caused by a change in the energy band structure when gas molecules are adsorbed on the nanowire surface. The nanoscale sensors are expected to be highly sensitive, with faster responses and can operate at room temperature, requiring low operating power. To increase gas selectivity, additional features can be added to the nanowire surface. Arrays of such nanowires mounted on a single chip will result in a highly versatile device that can be used for monitoring and sensing toxic gases in our immediate environment.