Quantum transport through a C48N12 based nanodevice
Abstract of thesis entitled
QUANTUM TRANSPORT THROUGH A C48N12 BASED NANODEVICE
for the Degree of Master of Philosophy
at The University of Hong Kong
in December 2004
The aim of this thesis study is to investigate quantum transport through a C48N12 based nanodevice. This novel C48N12 doped-fullerene molecule has attracted great attention due to their remarkable structural and electronic properties. The transport properties of the Al-C48N12-Al system under external bias and gate potentials have been investigated using an ab initio method developed by a research group in McGill University led by Prof. H. Guo. Their method is based on density functional theory combining nonequilibrium Green? function. A good understanding of the general transport features observed in the nanoscale devices has been obtained from the electronic structure of the system. Detail analysis of the transport properties of the C48N12 molecular systems
has been performed. These properties are mainly influenced by the interactions between the molecules and electrodes. Calculations show that conductance is sensitive to charge transfer between the molecule and the electrode at equilibrium. This charge transfer can align the lowest unoccupied molecular or-bital(LUMO) of the C48N12 molecule to the Fermi level of the Al electrodes, so it can inhibit the conductance of the molecular system, which has been explained through investigations of the C48N12 molecular systems for three different orientations of the molecule.
Based on the Landauer formalism, the current-voltage characteristics of the nanoscale systems have been calculated. The IV characteristics have been explained from a simple picture of shifting the mediating channels under the external bias voltage.
The transport properties of this molecular system were further investigated by calculation under gate potential coupled to the molecule. As a result, this external potential can switch the device from an insulating state to a metallic state which shows that this nanoscale device can be produced as a field-effect molecular current switch in future.
School:The University of Hong Kong
School Location:China - Hong Kong SAR
Source Type:Master's Thesis
Keywords:electron transport nanotechnology
Date of Publication:01/01/2005