Depth measurements of etch-pits in GaN with shape reconstruction from SEM images.
ABSTRACT The method, which allows shape reconstruction by reading the intensity from the scanning electron microscopy image, is presented and discussed in details. The method is applied to read the morphology of etch-pits, which were formed on the GaN surface by etching in molten KOH-NaOH eutectic mixture to delineate dislocations. The etch-pit depth distributions are obtained and used to determine densities of pits related to screw, mixed or edge-type dislocations. The results are compared with atomic force microscopy.
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Conference Paper: Analisys of positron focusing section for SPring-8 linac[Show abstract] [Hide abstract]
ABSTRACT: In the SPring-8 positron beams will be used and generated in the linac. In this paper, simulations and experiments of a test apparatus for the convertor are described. Results of simulations are qualitatively coincident with that of experiments, and from simulation results, an electron/positron conversion efficiency of 0.5% is obtained at the end of the convertor, with a feasible design of the convertor system. A future plan of superconducting magnet system for the convertor is also mentionedParticle Accelerator Conference, 1995., Proceedings of the 1995; 06/1995
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ABSTRACT: The methodology for fracture analysis of polymeric composites with scanning electron microscopes (SEM) is still under discussion. Many authors prefer to use sputter coating with a conductive material instead of applying low-voltage (LV) or variable-pressure (VP) methods, which preserves the original surfaces. The present work examines the effects of sputter coating with 25 nm of gold on the topography of carbon-epoxy composites fracture surfaces, using an atomic force microscope. Also, the influence of SEM imaging parameters on fractal measurements is evaluated for the VP-SEM and LV-SEM methods. It was observed that topographic measurements were not significantly affected by the gold coating at tested scale. Moreover, changes on SEM setup leads to nonlinear outcome on texture parameters, such as fractal dimension and entropy values. For VP-SEM or LV-SEM, fractal dimension and entropy values did not present any evident relation with image quality parameters, but the resolution must be optimized with imaging setup, accompanied by charge neutralization. SCANNING 00: 1-9, 2012. © 2012 Wiley Periodicals, Inc.Scanning 08/2012; · 1.29 Impact Factor