Kinetic Monte Carlo Simulation of Defect-Mediated Organization in Quantum Dot Self-Assembly
D. Gao, A. Kaczynski and J.A. Jaszczak
Michigan Technological University, US
quantum dot, self-assembly, spatial organization, kinetic Monte Carlo
A good understanding of quantum dot (QD) self assembly not only has the potential to augment standard materials patterning technologies but also has applications in industrial nanostructure fabrications. Many observations and insights about self-assembled quantum dots have been reported, but useful mechanisms for controlling the spatial ordering of self-assembled quantum dots remains a challenge. We propose that growing spiral steps emerging from screw dislocations can interact with diffusing impurities to form spatially-ordered, self-assembled quantum dot arrays. We have developed an atomistic solid-on-solid (SOS) model of a (001) surface of a simple cubic crystal and carried out Kinetic Monte Carlo (KMC) simulations to investigate this hypothesis. We studied the effects of interaction energies, diffusion lengths, temperature, and chemical potential on the growth rates, step flow, kink motion and impurity diffusion and segregation. Under appropriate conditions the impurity atoms clustered together at the corners of the growth spiral. Our results suggest that a screw-dislocation-generated growth spirals may be employed as a template for controlling of the spatial organization in quantum dot self-assembly.
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Nanotech 2005 Conference Program Abstract