Molecular beam epitaxy growth of GaN under Ga-rich conditions investigated by molecular dynamics simulation

Molecular beam epitaxial growth of GaN under Ga-rich conditions was simulated using a classical molecular dynamics method. We investigated nitrogen incorporation into the growth surface and the initial growth process using two kinds of simulation models: the Ga adlayer model and Ga droplet model. The simulation of the Ga adlayer model showed that the injected N atom diffused through the Ga adlayer and nucleation occurred in the solid/liquid interface. The simulation of the Ga droplet model showed that the injected N atom diffused on the bare GaN crystal surface and nucleation occurred at the edge of the Ga droplet. In the both simulations, scattering of injected N atoms on the surface of the Ga layer was often observed. Because Ga atoms in the Ga layer were intensively moving compared with that in the GaN crystal, injected N atoms were probably scattered by collisions with the Ga atoms in the Ga layer.