High-pressure in-situ diffraction studies of nanocrystalline (20 nm in
diameter) pure-hexagonal GaN were performed up to 20 GPa in Diamond
Anvil Cell (DAC, station F3 at Hasylab, Hamburg). It was found that
high-pressure treatment leads to transitions in polytype structure of
nanocrystalline GaN.
A simple model of introduction of stacking faults by random shifts of
(0001) planes was used for simulation of strain-induced disordering
process in nanocrystals.
Polytype structures resulting from simulation of disordering process
were applied to create atomic models of GaN crystallites (up to 16 nm
in diameter). Powder diffraction patterns were calculated for those
crystallites using Debye formula in its literal form.
A good agreement between diffraction patterns simulated by introducing
0.8-1.2 Shifts Per Layer (SPL) and those experimentally measured under
pressures of 14-20 GPa has been obtained.
The model proposed might explain why disordering arises in small
grains under high pressure.
Hypothetical high-pressure behavior of 2H, 3C, 4H, 6H and 8H polytypes
is also discussed.
Acknowledgements
This work was supported by the State Committee for Scientific
Research, Grants No. 7/T08A/036/18 and 7/T08A/030/19.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/254 must be provided.

1. Initial abstract
2. 2nd abstract
3. Real Time Characterisation of nanoMaterials
4. Analysis of density waves in CdSe, SiC, and diamond nanocrystals by application of NanoPDF software package to experimental Pair Distribution Functions.
5. Crystallite size determination from diffraction data: a do-it-yourself tutorial.  
6. Diamond-tungsten carbide nanocomposite
7. Reliable XRD characterization in production or high-throughput laboratory regime
8. GaN substrates with variable surface miscut for laser diode applications
9. Semipolar (2021) UV LEDs and LDs grown by PAMBE
10. High-pressure diffraction study of structural and elastic properties of zircon-type and scheelite-type RVO₄ (R = Nd, Eu)
11. Looking at the real structure of nanocrystals with powder diffraction: the apparent lattice parameter approach
12. Localization of rare-earth dopants in the lattice of nanocrystalline ZrO₂ - EXAFS study
13. Looking beyond limitations of diffraction methods of structural analysis of nanocrystalline materials
14. X-ray and electron microscopy techniques studies on nanocrystalline MgO powder materials prepared by sol-gel method
15. Statystyczna analiza deklarowanych kierunków rozwoju nowoczesnych materiałów w projekcie FOREMAT w powiązaniu z tematami polskich prac doktorskich, habilitacyjnych i grantów KBN
16. Error bars in powder diffraction
17. Synthesis of doped ZnO nanopowders in microwave hydrothermal reactors
18. Characterization of nanopowders
19. Combining microwave and pressure techniques for hydrothermal synthesis of ZnO and ZrO₂ nanopowders doped with a range of metal ions
20. Luminescence properties of zinc oxide nanopowders doped with Al ions obtained by the hydrothermal and vapour condensation methods.
21. Structure of nanocrystalline powders of MgO prepared by sol-gel method
22. Microwave technique applied on the hydrothermal synthesis and sintering of calcia stabilized zirconia nanoparticles
23. Yttrium-Aluminum Garnet Synthesized in the Medium of Supercritical Fluids
24. Growth of GaN layers on silicon and sintered GaN nano-ceramic substrates – TEM investigations
25. Doping of ZnO nanopowders with Mn, Ni and Cr In an ultrasound and microwave driver hydrothermal reaction
26. Localization of rare-earth dopants in the lattice of nanocrystalline ZrO₂ - EXAFS study
27. Characterization of nanocrystalline ZrO₂ doped with Rare-Earth elements synthesized via High Pressure Hydrothermal Method
28. Structure studies on nanocrystalline MgO powders prepared by sol-gel method dried under different conditions
29. Morphology of Al doped Zinc Oxide Obtained using Hydrothermal and Vapour Condensation Methods
30. Growth and properties of ytterbium doped KY(WO₄)₂ nanocomposites
31. Doping of ZnO nanopowders with Mn and Cr in an ultrasound and microwave driven hydrothermal reaction
32. Investigations of phase composition and grain size distribution in Pr doped ZrO2
33. Dyfraktometryczna analiza mikro- i makro-naprężeń w spiekach i kompozytach otrzymanych pod wysokim ciśnieniem i wysoką temperaturą.
34. Badania własności termicznych nanokryształów metodami dyfraktometrycznymi
35. Morphology of Al doped zinc oxide obtained by the vapour condensation method
36. Accuracy of XRD size measurements of nanocrystals
37. Morphology of Al-Doped Zinc Oxide Obtained by the Vapour Condensation Methods
38. Structure of nano-crystals: a key to understanding the unique properties of nano-materials
39. Application of XRD diffraction methods for determination of grain size distribution in nanoparticles
40. Fabrication and micro-structure characterization of Al2O3/Ni-P composites with interpenetrating phases
41. Nanocrystalline SiC compacts obtained by sintering of laser synthesized nanopowders under extreme pressures
42. High-pressure Induced Structural Decomposition of RE-doped YAG Nanoceramics
43. Sintering of nanopowders under high pressure
44. Synthesis and properties of GaAs nano-composites
45. MD simulation of atomic structure of nanocrystals
46. SiC-Zn nanocomposites obtained using high-pressure infiltration technique
47. Sintering temperature effect on structure and properties of Al2O3/Ni-P composites with interpenetrating phases
48. Grain Size and Grain Size Distribution of Nanocrystalline Pr-doped Zirconia Powders Obtained in High Pressure Microwave Reactor
49. Influence of synthesis conditions on the particles size and the morphology of zinc oxide nanopowders
50. Measuring the Grain Size Distribution of Pr-doped Zirconia Nanopowders obtained by Microwave Driven Hydrothermal Synthesis
51. Structural and luminescence properties of yttrium-aluminum garnet (YAG) nanoceramics
52. Fabrication and electrical properties of Eu³⁺:BaTiO₃ nanoceramics for SOFC
53. Analytical expression for Diffraction Line Profile for polydispersive powders
54. FW1/5-4/5M method for determination of the Grain Size Distribution from powder diffraction line profile
55. Dyfrakcyjne badania mikrostruktury polikryształów nanometrowych poddawanych działaniu wysokiego ciśnienia
56. X-ray diffraction studies of thermal properties of bulk- and surface-atoms of nanocrystalline SiC
57. Characterization of nanostructured hydroxyapatite ceramics densified at high-pressure and temperature
58. Powder precursors for nanoceramics: cleaning and compaction
59. Examination of the atomic Pair Distribution Function (PDF) of SiC nanocrystals by in-situ high pressure diffraction
60. Investigation of the microstructure of SiC-Zn nanocomposites by microscopic methods: SEM, AFM and TEM
61. Sythesis of metal-ceramic nanocomposites by high-pressure infiltration
62. X-Ray investigations of the natural and artificial White Etching Layer
63. Zinc oxide nanopowders obtained by the microwave-hydrothermal route
64. Microwave driven hydrothermal synthesis of Pr-doped zirconia nanopowders
65. The influence of temperature and pressure on possibility of obtaining Al₂O₃/Ni-P nanocomposite through hot pressing process.
66. Precise determination of full Grain Size Distribution from diffraction peak profile as a result of kinematical theory of diffraction for polidispersive nanomaterials
67. X-Ray Characterization of Nanostructured Materials
68. Generetion and Relaxation of Strain in SiC and GaN under Extreme Pressure
69. Surface Diffraction Effects from Nanopowders under Pressure
70. Transformation of fractal microstructure of nanocrystalline SiC and diamond in high pressures - Small Angle Scattering Study
71. Synthesis of Nanocomposites Based on Superhard Ceramic Nanopowders