Double-heterostructures were created on a treated GaAs substrate, and the density of dark defects was measured by means of electroluminescence microscopy. It was found that a dark-defect density of less than 105/cm2 was obtained when the As-terminated GaAs surface was Zn-treated. Such a treatment prevented the formation of Ga2Se3 layers. It was noted that H-radical exposure, before and during the Zn/As treatment, effectively removed excess ZnAsx compounds, and the density of dark defects fell to 2 x 104/cm2.

A.Taike, M.Kawata, T.Kikawa, M.Momose, J.Gotoh, S.Nakatsuka: Journal of Applied Physics, 1997, 81[9], 6165-70