Investigation of Molecular Adsorption Effect on the Electrical Properties of CNT-Based Sensors

The development of nanotechnology has generated enormous potential to build highly sensitive, low cost, and fast response sensors. High surface-to-volume ratio of nanomaterials is ideal for sensing phenomena. Moreover carbon nanotubes (CNTs) with extraordinary electrical features have been used in the improvement of the sensing center for different sensors. The variations in CNTs’ properties can be detected by several methods. CNTs have unique electronic properties and depending on their radius or chirality, they can show metallic or semiconducting behavior. Any mechanical deformation, chemical doping, or atomic structure deviations caused by molecular adsorption on CNT can change the electronic properties of it. Such changes in electrical properties make CNT-based sensors to be very sensitive to their sensing environment. In this paper, the effects of target molecules adsorption on electrical features of CNT-based sensors are modeled. The molecular adsorption effect on the Hamiltonian of the system based on tight-binding model is analyzed. The band structure of the system is investigated analytically. Then, deviations in the band structure and density of states based on band gap variations are discovered.