Title :
On transport properties of CNT metal/semiconductor/metal heterostructures using first principles methods
Author :
Bai, Ping ; Lam, Kai-Tak ; Chang, Ken Kai-fu ; Li, Erping
Author_Institution :
Comput. Electron. Group, Inst. of High Performance Comput., Singapore
Abstract :
The electron transport properties of carbon nanotube (CNT) metal/semiconductor/metal heterostructures are investigated using the first principles method based on density functional theory (DFT) and non-equilibrium Green´s function (NEGF). The atomic heterostructures are constructed by sandwiching a zigzag semiconducting CNT between two zigzag metallic CNTs with different diameters. The density of states, transmission function, conductance and current-voltage characteristics of the constructed heterostructures are simulated using the DFT-NEGF method. Results show that the imperfect interface in the CNT heterostructures affects the high-bias conductance significantly. The reduction of high-bias conductance is proportional to diameter ratio of two CNTs connected. The diameter of metallic CNT decides the threshold voltage and low-bias conductance of the heterostructures. The larger the diameter is, the lower the threshold voltage is and the higher low-bias conductance is.
Keywords :
Green´s function methods; carbon nanotubes; density functional theory; electronic density of states; elemental semiconductors; metal-semiconductor-metal structures; semiconductor nanotubes; C; CNT metal-semiconductor-metal heterostructures; DFT; DFT-NEGF method; NEGF; atomic heterostructures; current-voltage characteristics; density functional theory; density of states; electron transport properties; first principles method; high-bias conductance; metallic CNT; nonequilibrium Green function; threshold voltage; transmission function; zigzag semiconducting CNT; Carbon nanotubes; Current-voltage characteristics; Density functional theory; Electrodes; Electrons; Green´s function methods; High performance computing; Nanotechnology; Semiconductivity; Threshold voltage; CNT heterojunction; Modeling; electron transport; first principles method; metallic CNT electrode;
Conference_Titel :
Nanotechnology, 2007. IEEE-NANO 2007. 7th IEEE Conference on
Conference_Location :
Hong Kong
Print_ISBN :
978-1-4244-0607-4
Electronic_ISBN :
978-1-4244-0608-1
DOI :
10.1109/NANO.2007.4601251
