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Kinetic Monte Carlo Study on the diffusion mechanism of Au cluster on Au Substrate

Kinetic Monte Carlo(KMC) algorithm are used to simulate the evolution of Au cluster on the Au substrate . The morphology of the thin film and detailed diffusion mechanism can be demonstrated in this study. Molecular dynamics simulation (MD) is used to determine the energy barrier(activation energy) of an Au atom adsorbed on the clean surface of the substrate. Then, the thin cluster evolution process, surface reaction and surface diffusion of the Au atoms is modeled by KMC method. The morphologies of the clusters at different temperatures with different number of atoms are also investigated. The simulation results are compared with literature on experimental results to demonstrate the diffusion mechanism, which is difficultly observed in experiments.
A three-dimensional KMC simulation model is used in this study. The results are compared with those from experiments in order to identity the reliability of this KMC model and to modify this model. Nudged Elastic band simulation is used to determine the adsorption energy barrier of an Au atom on a clean Au substrate surface. From the KMC result a surface diffusion of Au migration process is proposed. The effect of the substrate temperature, and the number of atoms duration on the morphology of the Au cluster is obtained. The simulation results show a pyramid structure is built and collapsed from the corner and edge atoms fellow suit and then the atoms of top layers do so as well. Then results indicate that it is possible to to produce nano-gold (metal)-pyramid from Au cluster s by 1, melting clusters in short period and then quenching them, or 2. Depositing Au atoms at lower temperature as well as 500 K with
controlled rate.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0302109-160126
Date02 March 2009
CreatorsHsu, Wen-chun
ContributorsTzu-Kung Chang, Tai-Fa Young, Wang-Chuang Kuo, Shin-Pon Ju
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0302109-160126
Rightswithheld, Copyright information available at source archive

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