Molecular dynamics of irradiation-induced defect production in GaN nanowires
W Ren and A Kuronen and K Nordlund, PHYSICAL REVIEW B, 86, 104114 (2012).
We have used classical molecular dynamics methods to simulate the defect production of small-cross-section GaN nanowires by Ar ion irradiation. We performed 200 random individual ion impacts in the energy range of 30 eV to 10 keV for each nanowire. We found that the defect production for all nanowires was greatly enhanced in the low ion energy range below 3 keV, while at higher energies the defect production decreased due to the increasing transmission of ions through small-cross-section nanowires. Owing to the strong surface enhancement of defect production, in the low-energy range, the defect production in the nanowires was increased by a factor of 2 compared to bulk GaN. A simple model to estimate the irradiation energy dependence of the damage production in a nanowire was developed. It is based on the Gaussian energy deposition profile, and it gives the irradiation energy of the maximum damage in a reasonable agreement with the simulation results.
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