ARSENIC CAP LAYER DESORPTION AND THE FORMATION OF GAAS(001)C(4X4) SURFACES

GaAs(001)c(4X4) surfaces were obtained in the 380-450 degrees C temper ature range by thermal desorption of As cap layers from substrates pre pared by molecular beam epitaxy. Although reflection high-energy elect ron diffraction patterns showed little change in the temperature range explored, in situ scanning tunneling microscopy and Auger spectroscop y, complemented by ex situ atomic force microscopy, indicate that in t he lower-temperature range examined up to 11%-12% of the surface may s till be occupied by adsorbed As in the form bf wires and particles pre ferentially oriented along[100] directions. (C) 1995 American Vacuum S ociety.