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Abstract
Nanotechnology is widely considered to profoundly advance multiple industrial sectors. Due to the high costs, low resolution and confounding issues with experimental studies, atomistic Molecular Dynamics (MD) and Monte Carlo (MC) simulations offer an attractive means to study and address the yield and quality issues in the synthesis of nanostructures. However, current atomistic simulations are hampered by the huge computational overheads. Consequently, they are confined to modeling only the early stages of nanomanufacturing processes. We present a novel nanoinformatics approach using a multi-step local Gaussian process model to capture the nonlinear and nonstationary dynamics of growth process to accelerate MC simulation of nanomanufacturing process, such as synthesis of carbon nanotube (CNT) in chemical vapor deposition. The key idea is that the simulated CNT growth increments were found to exhibit nonlinear, recurring near-stationary dynamics, and lifting the tube structure by the predicted growth increment can put it to near optimum position. Results show that the present approach can save more than 80% of the computational effort as in traditional MC simulation, leading to the growth of one of the largest CNTs (194 nm long) from atomistic simulations.
Keywords
Monte Carlo, nanoinformatics, carbon nanotube synthesis, nonlinear, near-stationary dynamics
(ProQuest: ... denotes formulae omitted.)
1. Introduction
Nanotechnology products market is projected to exceed $1 trillion in the next 10 years [1, 2]. While some nanostructures and products, including tube, film and porous material, are considered for niche applications in automotive, aerospace, construction, medical and defense industries [3-10], much of the synthesis process, and related device development efforts remain confined to research labs. Carbon nanotubes (CNTs) [11, 12] are one of the promising nanostructure materials considered for those applications. CNTs are usually synthesized using chemical vapor deposition (CVD) process. While efforts have been made to address the optimization of the CVD process [13-15], the current CNT production and yield rates remain rather low to permit wider industrial application. Translating these nano-synthesis processes into viable manufacturing technologies is an imperative for the realization of the market potential, and the understanding of CNT growth mechanism is critical for this translation.
Different approaches have been taken to study the CNT synthesis mechanism, such as experimental study [16-20], continuum modeling simulation [21, 22] and atomistic simulation, including Molecular dynamics (MD)/Monte Carlo...