COMPUTATION OF THE TIME-DEPENDENCE OF DYNAMIC AND KINEMATIC RHEED INTENSITIES FOR GROWING SURFACES

The time dependence of the dynamic (i.e., multiple scattering) and kinematic (i.e., single scattering) RHEED intensities is computed for a model of a growing GaAs(001) surface. The surface was constructed using Monte Carlo simulation on a 7 x 7 lattice. Two incident beam angles were used, one corresponding to an out of phase condition for monolayers and the other corresponding to an out-of-phase condition for bilayers. For the dynamic intensities for these two angles completion of bilayers occurs at peaks of the specular beam intensity. To calculate kinematic intensities a model is developed to include the effects of refraction and damping in the 0th order wavefunctions. It is shown that kinematic intensities for the specular and a few other beams at the out-of-phase condition for bilayers agree with the dynamic results. For the remaining beams the kinematic results are very different from the dynamic results. At the monolayer out-of-phase condition kinematic intensities do not agree with the dynamic intensities for any beam. Some comments are made about the procedure used to include refraction and damping and the implications of the results are briefly discussed.