Comparison of Electronic Transport Parameter of CNT(10,10)/CNT(17,0) and CNT(5,5)/CNT(8,0) Carbon Nanotube Metal-Semiconductor On-Tube Heterojunction

Abstract

Carbon nanotubes research is one of the top five hot research topics in physics. It is because of its unique properties and functionalities, which leads to wide-range applications. One of the most interesting potential applications is in term of nanoelectronic device. There is a possibility to found some unique structure, where different carbon nanotubes are connected coaxially. It has been modeled carbon nanotubes heterojunction, which was built from two different carbon nanotubes, that one is metallic and the other one is semiconducting. There are two different carbon nanotubes metal-semiconductor heterojunction. The first one is built from CNT (10,10) as metallic carbon nanotube and CNT (17,0) as semiconductor carbon nanotube. The other one is built from CNT (5,5) as metallic carbon nanotube and CNT (8,0). All of the semiconducting carbon nanotubes are assumed to be a pyridine-like N-doped. Those two heterojunctions are different in term of their structural shape and diameter. It has been calculated their charge distribution and potential profile, which would be useful for the simulation of their electronic transport properties. The calculations are performed by using self-consistent method to solve non-homogeneous Poisson's equation with aid of universal density of states calculation method for carbon nanotubes. The calculations are done by varying the doping fraction of the semiconductor carbon nanotubes. It is obtained that the charge are distributed almost evenly along the semiconducting carbon nanotubes and the potential profile peaks in the vincinity of semiconducting carbon nanotubes center position, with some valley-shapes that show some sign of charge confinements nearby. However, from the comparison of two different heterojunctions, it could be inferred that the geometrical aspects of the heterojunction building blocks has effect on their electronic transport parameter. It is also obtained the calculation results of the electron tunneling transmission coefficient that transported through the heterojunction, which has energy lower than the potential barrier value.