Interactions between hydrogen and group VI donors in GaAs and GaAlAs

GaAs and GaAlAs layers doped with different group VI donors (S, Se, Te) have been exposed to hydrogen plasma. By secondary ion mass spectroscopy, it is shown that, as in Si-doped materials, the hydrogen diffusion strongly depends on the AlAs content. Electronic transport measurements indicate that after hydrogen diffusion the electron concentration systematically decreases and their mobility increases, demonstrating clearly the passivation of the group VI donors by hydrogen.