Morphology of Ionic Crystal Surface Structured by ESD Using a Line-scan of Electrons

Abstract

Surfaces of KCl crystals irradiated uniformly by scanning of 5 keV beam of electrons collimated with one direction are observed by an atomic force microscope (AFM). The irradiation doses are in the range up to 10 16 cm-2. The surfaces remain many overlapped terraces of sub-micron with random orientations. They are hard to be associated with the square pits observed in well known layer by layer desorption measurements in the dose range of 10 14 cm-2. The desorption process is simulated by a model based on the assumption that the low-coordinated sites act as the precursors for desorption. We have introduced parameters into this model to reproduce the oscillating structure of the particle-yields of the layer by layer desorption. The resultingˆnal morphology in the dose range of 10 16 cm-2 shows that many overlapped terraces are created with random orientations, whose terrace-lengths are small compared with that observed. The morphologies show that the process assumed to reproduce the layer by layer desorption can lead the multi-layer steps on the surface.

Growth of Au Particles Evaporated on KBr and KCl Substrates Wearing Increased Densities of Surface Steps

“…5 with our previous results, the surfaces in the HV condition are relatively contaminated 12,15) . We could not observe distinct overlapped pyramidal steps on these surfaces.…”

“…Although the observed morphologies of the surfaces irradiated in the HV chamber were not as clean as those irradiated in the UHV chamber, our previous studies under the UHV conditions show a minimal number of circular monolayer pits for overlapped steps in the ‰uence range of 10 14 cm -2 , and irregular pyramidal steps in the range of 10 15 cm - 2 15) . Thus the pyramidal steps result from overlap of rectangular monolayer pits by ESD 15) . The step density and especially the density of the overlapped steps increases with increasing electron ‰uence in the 10 15 cm -2 range 15,16) .…”

“…Thus the pyramidal steps result from overlap of rectangular monolayer pits by ESD 15) . The step density and especially the density of the overlapped steps increases with increasing electron ‰uence in the 10 15 cm -2 range 15,16) . In Fig.…”

Simulation of Intensity Oscillation of Planar Surface-channeling Protons Scattered on KBr Surface Irradiated by Electrons

“…The scenario of the ESD must be described by parallel and continuous series of individual processes. However, to our knowledge, there has been no report of a model that simulates the development of morphologies with electron ‰uence based on aˆrm scenario, except for a technical one that was previously reported by ourselves, which treats only theˆnal desorption process 5) . In the present work, a numerical method is used to prepare the ESDdecorated surfaces, oŠ of which the protons are scattered.…”

“…In one of our previous works, the ESD surfaces were formed by considering only the emission of atoms by recombination of the excited (mobile) F-centers (F * -centers) with the surface atoms as theˆnal process of the ESD 5) . The surfaces formed in the present work have not been previously used in the ion-trajectory simulation.…”