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Polishing Procedure (polishing + procedure)

Distribution by Scientific Domains

Physics and Astronomy	50%

Selected Abstracts

Investigation of ZnO substrates: effects of high temperature annealing

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007
S. Graubner
Abstract In order to promote growth of ZnO films on ZnO substrates, defects introduced by the surface polishing procedure have to be removed. We investigate the influence of high temperature annealing in O2 -atmosphere on the structural properties of the ZnO substrates by atomic force microscopy. Only at temperatures above 1100 °C atomic steps (terraces) are seen, the remaining defects can be assigned to dislocations in a density between 104 to 105 cm,2. Interestingly the electrical properties also change from high resistive to n-type conduction, which make the substrates , apart for the homoepitaxial growth on a perfect template , suitable for top-to-bottom contacts. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Wafer reuse for repeated growth of III,V solar cells

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2010
G. J. Bauhuis
Abstract The epitaxial lift-off (ELO) technique can be used to separate a III,V solar cell structure from its underlying GaAs or Ge substrate. ELO from 4-inch Ge wafers is shown and 2-inch GaAs wafer reuse after lift-off is demonstrated without degradation in performance of the subsequent thin-film GaAs solar cells that were retrieved from it. Since a basic wet chemical smoothing etch procedure appeared insufficient to remove all the surface contamination, wafer re-preparation is done by a chemo-mechanical polishing procedure. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Two-year follow-up of fractured anterior teeth restored with direct composite resin: report of three cases

DENTAL TRAUMATOLOGY, Issue 5 2008
Emre Ozel
Fractures of maxillar central incisors including enamel and dentin were diagnosed. Beveling with diamond bur was performed in all four cases. Dentin was cleaned with tungsten carbid bur. The teeth were etched with 37% phosphoric acid, restored with an adhesive system and microhybrid composite. Finishing and polishing procedures were performed by discs (Sof-Lex) and burs. Restorations were found successful according to modified United States Public Health Service (USPHS) criteria after 2 years in terms of retention, color match, marginal discoloration, secondary caries, marginal adaptation, and surface texture. [source]

Cathodoluminescence evaluation of subsurface damage in GaN substrate after polishing

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009
K. Y. Lai
Abstract The surface of HVPE grown GaN substrates were treated with two different polishing procedures. Both procedures were successful in producing highly smooth and featureless surfaces. However, subsurface damage was observed in the sample treated by one of the procedures. The subsurface damage was revealed by cathodoluminescence (CL) spectroscopy imaging but was not visible by scanning electron microscopy (SEM) or Atomic force microscopy (AFM). Thermal annealing at 950 °C with different gases was performed in an attempt to remove subsurface damages. Annealing in gas mixtures containing H2 increased both the presence of surface scratches and overall surface roughness. On the other hand, annealing in mixtures of NH3 and N2 (with no H2) led to the surfaces with significantly reduced subsurface damage. The surface roughness and optical properties of the sample after the annealing with such gas mixtures were slightly sacrificed. In order to evaluate subsurface damage depth, CL images were taken from the annealed surface for different acceleration voltages. The results suggest that the observed subsurface damages were within 1.48 ,m of the surface. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]