OXYGEN SCATTERING AND INITIAL CHEMISORPTION PROBABILITY ON GE(100)

We have studied the interaction of oxygen gas with both clean and oxygen-covered surfaces of Ge(100), over the temperature range from 300 to 900 K, using molecular beam scattering techniques. Results indicate that oxygen scatters primarily by direct inelastic scattering on the clean surface, but that considerable trapping occurs on the oxygen-covered surface. The variation of the initial sticking coefficient for dissociative chemisorption with surface temperature and incident oxygen molecular beam kinetic energy and incident angle can be explained in terms of a direct adsorption channel that becomes increasingly efficient at high beam normal kinetic energy and a precursor mediated channel that becomes increasingly efficient at low beam normal kinetic energy.