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Title: X-ray Characterization of Detached-Grown Germanium Crystals

Abstract

Germanium (1 1 1)-oriented crystals have been grown by the vertical Bridgman technique, in both detached and attached configurations. Microstructural characterization of these crystals has been performed using synchrotron white beam X-ray topography (SWBXT) and double axis X-ray diffraction. Dislocation densities were measured from X-ray topographs obtained using the reflection geometry. For detached-grown crystals, the dislocation density is on the order of 10{sup 4} cm{sup -2} in the seed region, and decreases in the direction of growth to less than 10{sup 3} cm{sup -2}, and in some crystals reaches less than 10{sup 2} cm{sup -2}. For crystals grown in the attached configuration, dislocation densities were on the order of 10{sup 4} cm{sup -2} in the middle of the crystals, increasing to greater than 10{sup 5} cm{sup -2} near the edge. The measured dislocation densities are in excellent agreement with etch pit density (EPD) results. Broadening and splitting of the rocking curve linewidths was observed in the vicinity of subgrain boundaries identified by X-ray topography in some of the attached-grown crystal wafers. The spatial distribution of rocking curve linewidths across the wafers corresponds to the spatial distribution of defect densities measured in the X-ray topographs and EPD micrographs.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914223
Report Number(s):
BNL-78791-2007-JA
Journal ID: ISSN 0022-0248; JCRGAE; TRN: US0801607
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Cryst. Growth; Journal Volume: 290; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CONFIGURATION; DEFECTS; DISLOCATIONS; GEOMETRY; GERMANIUM; NEUTRON DIFFRACTION; REFLECTION; SEEDS; SPATIAL DISTRIBUTION; SYNCHROTRONS; TOPOGRAPHY; X-RAY DIFFRACTION; NSLS; national synchrotron light source

Citation Formats

Volz,M., Schweizer, M., Raghothamachar, B., Dudley, M., Szoke, J., Cobb, S., and Szofran, F. X-ray Characterization of Detached-Grown Germanium Crystals. United States: N. p., 2006. Web. doi:10.1016/j.jcrysgro.2006.01.025.
Volz,M., Schweizer, M., Raghothamachar, B., Dudley, M., Szoke, J., Cobb, S., & Szofran, F. X-ray Characterization of Detached-Grown Germanium Crystals. United States. doi:10.1016/j.jcrysgro.2006.01.025.
Volz,M., Schweizer, M., Raghothamachar, B., Dudley, M., Szoke, J., Cobb, S., and Szofran, F. Sun . "X-ray Characterization of Detached-Grown Germanium Crystals". United States. doi:10.1016/j.jcrysgro.2006.01.025.
@article{osti_914223,
title = {X-ray Characterization of Detached-Grown Germanium Crystals},
author = {Volz,M. and Schweizer, M. and Raghothamachar, B. and Dudley, M. and Szoke, J. and Cobb, S. and Szofran, F.},
abstractNote = {Germanium (1 1 1)-oriented crystals have been grown by the vertical Bridgman technique, in both detached and attached configurations. Microstructural characterization of these crystals has been performed using synchrotron white beam X-ray topography (SWBXT) and double axis X-ray diffraction. Dislocation densities were measured from X-ray topographs obtained using the reflection geometry. For detached-grown crystals, the dislocation density is on the order of 10{sup 4} cm{sup -2} in the seed region, and decreases in the direction of growth to less than 10{sup 3} cm{sup -2}, and in some crystals reaches less than 10{sup 2} cm{sup -2}. For crystals grown in the attached configuration, dislocation densities were on the order of 10{sup 4} cm{sup -2} in the middle of the crystals, increasing to greater than 10{sup 5} cm{sup -2} near the edge. The measured dislocation densities are in excellent agreement with etch pit density (EPD) results. Broadening and splitting of the rocking curve linewidths was observed in the vicinity of subgrain boundaries identified by X-ray topography in some of the attached-grown crystal wafers. The spatial distribution of rocking curve linewidths across the wafers corresponds to the spatial distribution of defect densities measured in the X-ray topographs and EPD micrographs.},
doi = {10.1016/j.jcrysgro.2006.01.025},
journal = {J. Cryst. Growth},
number = 2,
volume = 290,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • No abstract prepared.
  • Anomalous X-ray scattering is a unique technique to determine the composition profile of quantum dots embedded in buried interfaces of multilayer-structures. Here we present the results of MBE grown Si/Ge multilayer structures on Si(001) substrates having self-assembled Ge quantum dots in its buried interfaces. We performed grazing incidence diffraction measurements of (400) reflections along with (004) diffraction profiles exhibiting super-lattice reflections at and away from the germanium K-edge. Systematic analysis of the acquired data enabled us to extract average composition and strain profiles of the quantum dots.
  • The (Lu{sub x}Gd{sub 0.995-x}Sm{sub 0.005}){sub 2}SiO{sub 5} single crystals with x=0.095, 0.11, 0.15, 0.17, 0.19 0.35 and 0.5 were grown by the Czochralski method. Structural properties were investigated by X-ray diffraction measurements. Unit cell parameters and cell volume were determined by the Rietveld refinement of the collected X-ray powder spectra. The segregation features between Gd and Lu were estimated and analyzed. Vibrational properties of the solid solutions were analyzed on the basis of polarized Raman spectra acquired at 300-875 K temperature range. Absorption and emission spectra of Sm{sup 3+} ion in the crystals with different composition were analyzed in themore » terms of dopant energy levels, oscillator strengths of transitions and spectral features of luminescence bands in the visible range. Both structural and optical investigations revealed that change of Lu{sup 3+} content in (Lu{sub x}Gd{sub 0.995-x}Sm{sub 0.005}){sub 2}SiO{sub 5} solid solution crystals induces the phase transition from C2/c (Lu{sub 2}SiO{sub 5}) to P2{sub 1}/c (Gd{sub 2}SiO{sub 5}) structure. It was found that the break of LSO to GSO-type structure occurs at 0.15<x<0.17. - Graphical abstract: Single crystals of Sm{sup 3+}-doped (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5} solid solutions have been grown by Czochralski method and characterized by various techniques. Crystal structure changes from C2/c to P2{sub 1}/c for composition with 0.15<x<0.17. Change of crystal structure causes changes in emission spectra. Highlights: Black-Right-Pointing-Pointer The (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5} crystals are an alternative to LSO and GSO hosts for applications. Black-Right-Pointing-Pointer The break of the P2{sub 1}/c to C2/c structure in (Lu{sub x}Gd{sub 1-x}){sub 2}SiO{sub 5}:Sm occurs for 0.15<x<0.17. Black-Right-Pointing-Pointer Temperature-induced phase transition from C2/c to P2{sub 1}/c up to 875 K was not observed. Black-Right-Pointing-Pointer Observed significant changes of emission spectra caused by P2{sub 1}/c to C2/c structural transition.« less
  • Abstract not provided.