The stoichiometry and reconstruction of the (001) surface were studied by using reflection high-energy electron diffraction and surface photo-absorption techniques. The experiments were carried out by using a solid-source molecular beam epitaxy system with a cracker cell as a P source. It was found that, when the amount of Ga that was supplied to the surface was greater than 2 monolayers, the 2 x 4 reconstruction that corresponded to the P-stabilized surface was observed in spite of the presence of excess Ga at the surface. It was concluded that the surface was Ga-terminated at up to 2 monolayers of Ga supply. The Ga atoms then moved to non-periodic sites such as Ga droplets.

M.Yoshikawa, A.Nakamura, T.Nomura, K.Ishikawa: Japanese Journal of Applied Physics 1, 1996, 35[2B], 1205-8