Mechanism of Aluminum Droplet Nucleation and Ripening on GaAs(001) Surface by Molecular Beam Epitaxy

study is conducted on the nucleation process of aluminum droplets on a GaAs(001) surface during droplet epitaxial growth, which reveals the influencing factors in the nucleation process, including the substrate temperature and the deposition rate, when other conditions are unchanged. In addition, the minimum atomic number for the initially incomplete state, the initially completed state and the completed state are calculated to be 1, 2 and 5, respectively. In the meantime, based on the extended thermodynamic model, the energy ( E_r) and ideal contact angle ( θ_0) in the process of droplet ripening and nucleation are 2.5 eV and 73.5°.