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Title: Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere

Abstract

Historically, the Stepanov method has been used for growing long shaped sapphire crystals (rods, tubes, and ribbons) for practical design. The recent intense development of this technique was stimulated by sapphire applications in optics and electronics; thus, the optical and structural quality of these crystals is of great importance. The results of studying the structural quality of sapphire rods up to 18 mm in diameter grown under optimized conditions are reported.

Authors:
; ; ;  [1]
  1. National Academy of Sciences of Ukraine, Institute for Single Crystals (Ukraine)
Publication Date:
OSTI Identifier:
22472400
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 60; Journal Issue: 2; Other Information: Copyright (c) 2015 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL GROWTH; CRYSTAL STRUCTURE; CRYSTALS; INVERTED STEPANOV METHOD; OPTICS; RODS; SAPPHIRE; TUBES

Citation Formats

Kryvonosov, Ye. V., Konevskiy, P. V., E-mail: kopamas@gmail.com, Lytvynov, L. A., and Tkachenko, V. F. Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere. United States: N. p., 2015. Web. doi:10.1134/S1063774515020133.
Kryvonosov, Ye. V., Konevskiy, P. V., E-mail: kopamas@gmail.com, Lytvynov, L. A., & Tkachenko, V. F. Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere. United States. doi:10.1134/S1063774515020133.
Kryvonosov, Ye. V., Konevskiy, P. V., E-mail: kopamas@gmail.com, Lytvynov, L. A., and Tkachenko, V. F. Sun . "Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere". United States. doi:10.1134/S1063774515020133.
@article{osti_22472400,
title = {Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere},
author = {Kryvonosov, Ye. V. and Konevskiy, P. V., E-mail: kopamas@gmail.com and Lytvynov, L. A. and Tkachenko, V. F.},
abstractNote = {Historically, the Stepanov method has been used for growing long shaped sapphire crystals (rods, tubes, and ribbons) for practical design. The recent intense development of this technique was stimulated by sapphire applications in optics and electronics; thus, the optical and structural quality of these crystals is of great importance. The results of studying the structural quality of sapphire rods up to 18 mm in diameter grown under optimized conditions are reported.},
doi = {10.1134/S1063774515020133},
journal = {Crystallography Reports},
number = 2,
volume = 60,
place = {United States},
year = {Sun Mar 15 00:00:00 EDT 2015},
month = {Sun Mar 15 00:00:00 EDT 2015}
}
  • The formation of blocks in shaped sapphire rods of two crystallographic orientations has been investigated. It is shown that, when growth occurs in the direction of the optical c axis, blocks are formed with a higher probability than in the case of growth in the a direction. A model of formation of blocks in rods of different orientations is proposed. The distribution of residual stresses over sapphire rod cross sections is measured by conoscopy. It is found that stresses increase from the middle of a rod to its periphery and reach 20 MPa.
  • A three-dimensional model is proposed for the global heat exchange during growth of basal-plane-faceted sapphire ribbons. The model is based on the method for solving three-dimensional problems of radiative heat transfer in complex regions with diffusely and specularly reflecting boundaries. The temperature distributions in the ribbon and elements of the thermal zone are investigated. It is shown that the developed model correctly reflects the main features of the processes of heat exchange in the crystallization setup and makes it possible to purposefully modify the thermal zone.
  • A mathematical model is proposed to describe the behavior of a doping impurity concentration in a crystal grown by the Stepanov method from a melt and subjected to periodic changes in its pulling rate and temperature of the thermal node. Various modes of these effects are discussed. The results obtained are given by graphs that characterize their influence on concentration distribution.
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