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Full-Text Articles in Life Sciences
Surface Diffusion And Islanding In Semiconductor Heterostructures, H. J. Gossmann, G. J. Fisanick
Surface Diffusion And Islanding In Semiconductor Heterostructures, H. J. Gossmann, G. J. Fisanick
Scanning Microscopy
Molecular beam epitaxy (MBE) is an important technique for the creation of new, non-equilibrium semiconductor materials and structures exhibiting novel physical phenomena. Surface diffusion plays an important role in the growth of these structures, influencing such fundamental growth processes and constants as islanding, critical thickness and epitaxial temperatures. Two approaches to the general problem of surface diffusion and islanding, using the SiGe system as a prototypical semiconductor heterostructure, are discussed: The time evolution of patterned deposits, and kinetic studies of nucleation and growth. While disordered laminar growth occurs for deposition at 300 K, elevated temperatures lead to Stranski-Krastanow (SK) growth …
Techniques For The Microanalysis Of Higher Plants With Particular Reference To Silicon In Cryofixed Wheat Tissues, M. J. Hodson, A. G. Sangster
Techniques For The Microanalysis Of Higher Plants With Particular Reference To Silicon In Cryofixed Wheat Tissues, M. J. Hodson, A. G. Sangster
Scanning Microscopy
The applications of x-ray microanalysis in research into silicon in higher plants are reviewed, recent developments are assessed, and new data are presented. Conventionally prepared material [air or freeze drying for scanning electron microscopy (SEM), and glutaraldehyde/osmium tetroxide fixation for transmission electron microscopy (TEM)) has been studied using both wavelength and energy dispersive microanalysis. These techniques are reliable provided that the deposited form of silica is the major focus of investigation. Recently, studies concerning the soluble, mobile forms of silica, and the ionic environment at deposition sites have been initiated. In these investigations x -ray microanalysis has been carried out …
Energy Loss Of Electrons Below 10 Kev, Hans Bichsel
Energy Loss Of Electrons Below 10 Kev, Hans Bichsel
Scanning Microscopy
Monte Carlo calculations are used to obtain the energy loss and spatial distribution of electrons penetrating matter. For this purpose, reliable cross section for the inelastic collisions must be known. As an approximation valid for large energy losses, the Coulomb cross section can be used. It can be modified in a simple way to account for the binding of electrons and for the exchange effect. In the Gryzinski model, collisions with moving electrons are assumed. In the quantum mechanical Bethe approximation, σ is closely related to the dipole oscillator strength (DOS), and its extension to finite momentum transfers, the generalized …
Electron Beam Nano-Etching In Oxides, Fluorides, Metals And Semiconductors, C. J. Humphreys, T. J. Bullough, R. W. Devenish, D. M. Maher, P. S. Turner
Electron Beam Nano-Etching In Oxides, Fluorides, Metals And Semiconductors, C. J. Humphreys, T. J. Bullough, R. W. Devenish, D. M. Maher, P. S. Turner
Scanning Microscopy
Etching, lithography, hole formation, surface restructuring and external machining can all be performed on a nanometre scale using an intense electron beam. Results are presented for a range of different materials which demonstrate the variety of mechanisms by which electron beam nano-etching can occur. For example, in crystalline 13-alumina hole formation occurs by surface indentations growing inwards to join up and form a nanometre diameter hole. In amorphous alumina, on the other hand, hole formation is from the inside-out: oxygen gas bubbles form under the electron beam, coalesce, and burst to leave a well defined nanometre diameter hole. In MgO …