학술논문

Modeling SWCNT Bandgap and Effective Mass Variation Using a Monte Carlo Approach
Document Type
Periodical
Source
IEEE Transactions on Nanotechnology IEEE Trans. Nanotechnology Nanotechnology, IEEE Transactions on. 9(2):184-193 Mar, 2010
Subject
Components, Circuits, Devices and Systems
Computing and Processing
Photonic band gap
Effective mass
Monte Carlo methods
Carbon nanotubes
Analytical models
Semiconductivity
Structural engineering
Nanostructured materials
Inorganic materials
Semiconductor materials
Bandgap variation
carbon-nanotube (CNT) device models
effective mass variation
single-walled CNT (SWCNT)
third-nearest-neighbor tight-binding (TB) model
Language
ISSN
1536-125X
1941-0085
Abstract
Synthesizing single-walled carbon nanotubes (SWCNTs) with accurate structural control has been widely acknowledged as an exceedingly complex task culminating in the realization of CNT devices with uncertain electronic behavior. In this paper, we apply a statistical approach in predicting the SWCNT bandgap and effective mass variation for typical uncertainties associated with the geometrical structure. This is first carried out by proposing a simulation-efficient analytical model that evaluates the bandgap ( $Eg$) of an isolated SWCNT with a specified diameter ($d$) and chirality ($\theta$ ). Similarly, we develop an SWCNT effective mass model, which is applicable to CNTs of any chirality and diameters >1 nm. A Monte Carlo method is later adopted to simulate the bandgap and effective mass variation for a selection of structural parameter distributions. As a result, we establish analytical expressions that separately specify the bandgap and effective mass variability ( $Eg_{\sigma}$ , $m_\sigma ^ *$ ) with respect to the CNT mean diameter ( $d_{\mu}$) and standard deviation ($d_{\sigma}$). These expressions offer insight from a theoretical perspective on the optimization of diameter-related process parameters with the aim of suppressing bandgap and effective mass variation.