We simulate the trajectories of backscattered electrons within a SEM of particular detection geometry which is adapted to topographic contrast attenuation and Z atomic number contrast enhancement. The calculations are performed choosing the different experimentally possible conditions as regards the primary electron energy, the detector aperture angle and the energy window of the detected electrons. From such simulations, it is possible to deduce the backscattering coe

The preparation of metal alloy and monoelemental nanoclusters in silica by Ag, Cu ion sequential implantation and annealing in selected oxidizing or reducing atmosphere is studied. The formation of metastable Ag-Cu alloy is verified in the as-implanted samples by optical absorption spectra, selected area electron diffraction and energy dispersive spectrometer spectrum. The alloy is discomposed at elevated annealing temperature in both oxidizing and reducing atmospheres. The different effects of annealing behaviors on the Ag-Cu alloy nanoclusters are investigated.

Ag nanoclusters embedded in silica matrix were formed by ion implantation to different doses. The intensity of surface plasmon resonance absorption enhances with the increasing of the implanted dose, but decreases at dose higher than 1

The Ag ions were implanted in an amorphous SiO2 film, which was placed in a sample chamber of TEM. The concentration and size distribution of the Ag nanocrystals as functions of both the ion dose and the annealing temperature were examined in-situ by using this TEM. The selected diffraction pattern determined the Ag nanocrystal's presence and the dark field micrograph showed the shape and the concentration of the Ag nanocrystals. The implantation results demonstrated an average size diminution and a significant concentration increase of the Ag nanocrystals when the dose increased. The annealing results showed a loss of silver at 300℃ and above.

We report on the formation of alloy nanoclusters in silica by Ag/Cu ion sequential implantation. The formation of alloy nanocluster has been evidenced by optical absorption spectra, selected area electron diffraction and energy dispersive X-ray spectra. The microstructure characters of nanoclusters have been studied by high resolution transmission electron microscopy. The lattice distortion of some nanoclusters has been observed. A model has been given to explain the distortion. Some defects (partial dislocation, stacking faults) have been found in nanoclusters.