Ab Initio Study of Doped Carbon Nanotube Sensors

Recently great advances have been made in demonstrating the viability of using carbon nanotubes (CNTs) to detect the presence of chemical gases such as NO2, NH3, and O2, and they have led to the design of a new breed of sensor devices. Based on intrinsic CNTs, the devices are capable of detecting small concentration of molecules with high sensitivity under ambient conditions. However, these devices have a limitation that only molecules binding to a carbon nanotube can be detected. They are currently limited to NH3, NO2, and O2, and a host of highly toxic gases (such as carbon monoxide), water molecules, and biomolecules cannot be detected using these intrinsic CNT devices. Recent efforts on externally functionalizing CNT surface and internal doping in CNT only result in temporary sensing capability due to the weak van der Waals interaction between CNT and doped materials. In this paper, we propose the concept of a new type of nanoscale sensor devices that can detect the presence of CO and water molecules....