Development of micron-scale crystal growth simulation by using the first-principles calculation

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The eptaxial growth simulation scheme and program codes are developed by using the linkage of the first-principles DFT calculation and the kinetic Monte Carlo simulation technique. The key parameters used in the kinetic Monte Carlo simulation is the migration barrier energy of adatom on the substrate surface. Though the barrier energies can be obtained by using the DFT calculation of the potential energy surface (PES) for each adatoms, it is almost impossible to calculate every patterns of environments of each adatom in the real situation during growth.In our study we decouple the barrier energies into the components of the first nearest atoms and the second nearest atoms. Using the DFT calculation, we obtain a lot of PES for Ga, In and As on InAs/GaAs(001) surface, Ga, N, Zn and O on GaN(0001), GaN(000-1), Zn0(0001), Zn0(000-1), SiC(0001), SiC(000-1) and sapphire(0001). These barrier energies determined with the PES calculation can be very useful for the kinetic Monte Carlo simulation of the epitaxial growth not only for homoepitaxy but also for heteroepitaxy.Using our simulation for InAs/GaAs(001), we found that the very initial stage of quantum dot formation is caused by the fluctuation of In/Ga atomic density on the wetting layer.