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U of I Only Seebauer, Edmund G. Schultz, Kurt Alan 2014-12-17T20:39:27Z 2014-12-17T20:39:27Z 10000-01-01 1992 1992 Surface diffusion of Sb on Ge(111) has been measured with the newly-developed technique of second harmonic microscopy. In this method, concentration profiles at submonolayer coverage are imaged directly by second harmonic generation with 5 $\mu$m spatial resolution. A Boltzmann-Matano analysis of the concentration profiles yields the coverage dependence of the diffusivity D without parameterization. Experiments were performed at roughly 70% of the bulk melting temperature T$\sb{\rm m}.$ In the coverage range of $0<\theta<0.6,$ the activation energy E$\sb{\rm diff}$ remains constant at 47.5 $\pm$ 1.5 kcal/mol. The corresponding pre-exponential factor decreases from 8.7 $\times$ 10$\sp{3\pm0.4}$ to 1.6 $\times$ 10$\sp{2\pm0.4}$ cm$\sp2$/sec. The results are explained in terms of a new vacancy model for surface diffusion at high-temperatures. The model accounts semiquantitatively for the large values of E$\sb{\rm diff}$ and D$\sb{\rm o},$ and suggest that these quantities may be manipulated by bulk doping levels and photon illumination of the surface. Made available in DSpace on 2014-12-17T20:39:27Z (GMT). No. of bitstreams: 1 9305686.pdf: 5943423 bytes, checksum: ba3269cd5f50915cf25a622412d95602 (MD5) Previous issue date: 1992 Embargo set by: Seth Robbins for item 72309 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs 202 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992. http://hdl.handle.net/2142/72141 (UMI)AAI9305686 Chemistry, Physical Physics, Condensed Matter Physics, Optics Surface Diffusion of Antimony on Germanium(111) Investigated by Second Harmonic Microscopy text Chemical Engineering Chemical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.