Sensitivity of angle resolved SIMS measurements of the O - polar angle distribution to surface, subsurface and defect oxygen sites on Al(100)

Abstract

Angle resolved secondary ion mass spectrometry measurements of the O - polar angle distribution have been performed on two Al(100) surfaces that contain different surface defect densities as a function of oxygen exposure at 300 K and as a function of thermal treatment following oxygen adsorption at 300 K. Correlation between the measured O - polar angle distributions and the surface structure, as determined from previous studies, indicate a sensitivity of the O - polar angle distribution to the population of oxygen in surface, subsurface and some defect sites. Oxygen atoms in surface sites on the (100) plane appear to preferentially eject at a polar angle of θ – 50° (as measured from the surface normal) while oxygen ejected from subsurface and some defect sites ejects at considerably smaller polar angles.