Simulation of GaN Nanocluster Droplet Epitaxy on Si(111) Substrate

In the present paper the process of GaN nanocluster droplet epitaxy on Si(111) substrate was investigated by Monte Carlo simulation. The Monte Carlo model is based on vapor-liquid-solid growth mechanism and basic processes of molecular beam epitaxy. We proposed the scheme of liquid gallium nitridation in nitrogen flux. The gallium atoms diffuse from the droplets and interact with nitrogen forming GaN islands. The higher binding energy of gallium atoms with nitrogen compared to that with silicon leads to pyramidal island shape that is result of enhanced Ga flux to the island top in comparison with such one to the base. Gallium nitride nanocluster crystallization takes place not under the gallium droplets but on the substrate surface outside them. In the result the cluster density is appeared to be higher than initial gallium droplet one. The model dependences of GaN nanocluster density on nitrogen flux and Ga drop density were obtained in this work.