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X-Ray Characterization of Structural Defects in Seeded and Self-Seeded ZnSe Crystal Grown by PVT in Horizontal and Vertical ConfigurationsAs part of a pre-flight ground based investigation of crystal growth of II-VI compound semiconductors, a number of ZnSe boules have been grown by physical vapor transport (PVT) at Marshall Space Flight Center. Boules were grown in both horizontal and vertical configurations and seeded and self-seeded growth techniques were employed. As-grown and/or cleaved boules were examined by a combination of synchrotron white beam x-ray topography (SWBXT) and high resolution triple axis diffraction (HRTXD) to characterized the structural defects and correlate them with the growth conditions. Horizontal grown boules tend to grow away from the ampoule wall (contactless growth) and generally exhibit large (110) facets parallel to the gravity vector. Vertical grown boules grew to the full diameter of the ampoule and exhibited no faceting. X-ray topography combined with back reflection x-ray diffraction revealed the presence of lamellar twins (180 deg type about the [111] axis) in horizontal grown boules while vertically grown boules contain a few large grains, some of which are twinned. X-ray topographs and reciprocal space maps recorded from the boules show the better crystal quality of horizontal grown boules. The relationship between crystal quality and gravity vector is investigated. Further, an attempt is made to extend the Hurle theory of twin nucleation in Czochralski grown crystals to explain the twinning mechanisms in horizontal grown boules.
Document ID
20010078917
Acquisition Source
Marshall Space Flight Center
Document Type
Abstract
Authors
Raghothamachar, B.
(State Univ. of New York Stony Brook, NY United States)
Dudley, M.
(State Univ. of New York Stony Brook, NY United States)
Su, C.-H.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Volz, H. M.
(Wisconsin Univ. Madison, WI United States)
Matyi, R.
(Wisconsin Univ. Madison, WI United States)
Whitaker, Ann F.
Date Acquired
August 20, 2013
Publication Date
January 7, 2001
Subject Category
Electronics And Electrical Engineering
Meeting Information
Meeting: 13th American Conference on Crystal Growth and Epitaxy
Location: Burlington, VT
Country: United States
Start Date: August 12, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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