New Phase Formation of Gd sub 2 O sub 3 on GaAs (100)

A fluorite-related phase of Gd sub 2 O sub 3, with a tetragonal unit cell of a = 5.65angstroms and c = 5.37angstroms, was attained in this study. The new phase was found either in a thin Gd sub 2 O sub 3 film (~18angstroms), which was epitaxially grown on GaAs (100), or in a disordered (by mild Ne sup + -ion sputtering) and recrystallized (by UHV annealing) thin cubic alpha-Gd sub 2 O sub 3 film. The structural characteristics of the new oxide films were studied using in-situ reflection high-energy electron diffraction, secondary-electron imaging, and single-crystal x-ray diffraction.