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The variation in the surface potential as a function of the ferroelectric polarization of micron scale domains in a thin epitaxial film of Pb(Zr0.48Ti0.52)O-3 is measured using mirror electron microscopy. Domains were written using piezoforce microscopy. The surface potential for each polarization was deduced from the mirror to low energy electron microscopy transition in the local reflectivity curve. The effect of extrinsic screening of the fixed polarization charge at the ferroelectric surface is demonstrated. The results are compared with density functional theory calculations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3523359]

Low energy electron irradiation of a Ag(111) surface during NO2 adsorption at 300 K induces formation of Ag oxide. Using a spatially confined electron beam, small Ag2O spots could be grown with a sharp, ∼100 nm wide, boundary to the nonirradiated metallic surface. Since the structure size will mainly depend on the sharpness of the irradiating electron beam, this process has the potential of a single step nanostructuring process. Temperature treatment offers an easy way to manipulate the boundary between oxide and metallic silver by steering a chemical front.

With laterally resolved photoemission spectroscopy, we obtained In and Ga surface concentration maps of InAs/GaAs quantum dots. Our data demonstrate that the dot composition is neither pure InAs nor homogeneous InxGa1-xAs, but presents an In concentration increasing from the borders to the center of the dots. Besides, our observations suggest strong In segregation (x ~ 0.9) on the surface of the dots and of the surrounding wetting layer. Such segregation, well known for two-dimensional InAs/GaAs growth, had not been directly observed so far on the dots, and should be taken into account to model size and composition of GaAs-overgrown structures.