Reactivity of III–V and II–VI semiconductors toward hydrogen: surface modification and evolution in air

In the present work, gallium arsenide is submitted to hydrogen radiofrequency plasma, and cadmium telluride either to hydrogen radiofrequency plasma, to hydrogen implantation by a Kaufman source or to annealing under molecular hydrogen gas. The different hydrogen treatments induce a modification of the surface stoichiometry, resulting in cation (Ga or Cd) enrichment compared to the initial chemically etched surface, and a deoxidation of the semiconductor surface. This new surface chemical state is more or less stable with respect to further oxidation in air ambient. This stability in air is correlated to the difference from stoichiometry (gallium or cadmium enrichment) and the simultaneous accumulation of hydrogen in the superficial layers of the compound.