Light-Induced Surface Diffusion

摘要: Surface diffusion of indigenous and/or foreign atoms plays a key role in number physical and chemical processes. To name few, it is important crystal growth epitaxy, heterogeneous catalysis, nucleation supported nanoparticles, so on. Finding reliable tool to control the surface processes an attractive goal for many modern technologies. Optical photons being absorbed by or species adsorbed onto can alter considerably. At lager intensities illumination these alternations are mainly due temperature rise, while at lower non-thermal mechanisms light-induced operative. The latter subjects this chapter. electronic excitation follows after photon absorption changes forces exerted atoms. After short period time energy partitioned between atom. excess obtained atom results increased desorption rates from as well over surface. An inhomogeneous leads steady state distribution situation similar Soret effect but require special theoretical consideration that presented unexpected result analysis spatial density non monotone. There pronounced maximum boundary illuminated dark regions. shapes metal nanoparticles via Volmer-Weber mode metastable. Heating known speed up equilibration particles shapes. In our experiments with silver sodium on dielectric surfaces we found evidences reversible particle Hence, substrate determines equilibrium shape nanoparticles. case sodium, speeds reshaping. This process rationalized terms nanoparticle surface, main step identified photo-induced detachment terraces. be rate limiting reshaping process.