SURFACE RECONSTRUCTION OF SULFUR-TERMINATED GAAS(001) OBSERVED DURING ANNEALING PROCESS BY SCANNING-TUNNELING-MICROSCOPY

The surface reconstruction of in-situ prepared sulfur-terminated (S-terminated) and sulfur-protected (S-protected) GaAs(001) is studied by scanning tunneling microscopy (STM) at high temperatures of up to 260 degrees C. We demonstrate a new reordering process from the (4 x 6) Ga-stabilized surface to the (2 x 6) S-stabilized surface and a novel method of air protection using a S passivation layer. Moreover, the in-situ observation of the annealing process of this S-protection layer is performed by high-temperature STM, avoiding the adsorption from environments and verifying that the (2 x 6) structure still becomes dominant on the S-terminated GaAs(001) surface without the effects of As atoms.