Electrical transport through heterojunctions of single-walled carbon/silicon carbide/carbon nanotubes

The transport properties of heterojunctions composed of SiC nanotubes (SiCNTs) with different length coupled between metallic carbon nanotubes (CNTs) have been investigated using a combined density-functional theory and nonequilibrium Green's function formalism. It is shown that the conductance of heterojunction decreases exponentially with the increasing length of SiCNT. The current-voltage curve of the system is linear for short SiCNT, but becomes gradually nonlinear for longer SiCNT, indicating a transition from metallic characteristics to semiconductor-like behavior. The observed trends can be understood by the electron tunneling between metallic CNTs. The present results provide insights into the physical mechanism of heterojunctions and are useful for their applications in electronic devices. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3673793]