Generation and Relaxation of Microstrains in GaN Nanocrystals under Extreme Pressures

• Authors: E. Grzanka , B. Palosz , S. Gierlotka , R. Pielaszek , U. Bismayer , J. Janik , J. Wells , F. Palosz , F. Porsch
• Languages of publication: EN

Abstracts

EN

Nanocrystalline powders of GaN with grain sizes ranging from 2 to 30 nm were examined under high external pressures by in situ diffraction techniques in a diamond anvil cell at DESY (HASYLAB, Station F3). The experiments on densification of pure powders under high pressure were performed without a pressure medium. The mechanism of generation and relaxation of internal strains and their distribution in nanoparticles was deduced from the Bragg reflections recorded in situ under high pressures at room temperature. The microstrain was calculated from the full-width at half-maximum (FWHM) values of the Bragg lines. It was found that microstrains in GaN crystallites are generated and subsequently relaxed by two mechanisms: generation of stacking faults and change of the size and shape of the grains occurring under external stress.

Keywords

EN

61.46.+w; 81.07.Wx

Discipline

• 81.07.Wx: Nanopowders

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2002
• Volume: 102
• Issue: 2
• Pages: 167-174

Dates

published

2002-08

received

2001-09-23

Contributors

author

E. Grzanka

• High Pressure Research Center UNIPRESS, Sokołowska 29/37, 01-142 Warsaw, Poland
• Institute of Experimental Physics, Warsaw University, Warsaw, Poland

author

B. Palosz

• High Pressure Research Center UNIPRESS, Sokołowska 29/37, 01-142 Warsaw, Poland

author

S. Gierlotka

• High Pressure Research Center UNIPRESS, Sokołowska 29/37, 01-142 Warsaw, Poland

author

R. Pielaszek

• High Pressure Research Center UNIPRESS, Sokołowska 29/37, 01-142 Warsaw, Poland
• Institute of Experimental Physics, Warsaw University, Warsaw, Poland

author

U. Bismayer

• Mineral-Petrographisches Institut, University of Hamburg, Hamburg, Germany

author

J. Janik

• University of Mining and Metallurgy, Cracow, Poland

author

J. Wells

• Department of Chemistry, Duke University, Durham, USA

author

F. Palosz

• USRA/NASA-Marshall Space Flight Center, Huntsville, Alabama, USA

author

F. Porsch

• Mineralogisch-Petrologisches Institut der Rheinischen Friedrich-Wilhelms-Universität Bonn, Bonn, Germany

References

• 1. J.F. Janik, J.R. Wells, Chem. Mater., 8, 2708, 1996
• 2. B. Bondars, S. Gierlotka, B. Palosz, S. Smekhnov, Mater. Sci. Forum, 166-169, 737, 1993
• 3. B. Palosz, S. Gierlotka, E. Grzanka, K. Akimow, R. Pielaszek, P. Biczyk, A. Grzegorczyk, S. Stel'makh, U. Bismayer, J.F. Janik, Mater. Sci. Forum, 378-381, 735, 2001
• 4. E. Grzanka, B. Palosz, S. Gierlotka, R. Pielaszek, K. Akimow, U. Bismayer, J.F. Janik, Annual Report Hasylab 2000, p. 481
• 5. E. Grzanka, B. Palosz, S. Gierlotka, R. Pielaszek, K. Akimow, U. Bismayer, J.F. Janik, Annual Report Hasylab 2000, p. 483
• 6. R. Pielaszek, S. Gierlotka, S. Stel'makh, E. Grzanka, B. Palosz, Defect and Diffusion Forum, 208-209, 189, 2002
• 7. J-W. Hwang, J.P. Campbell, J. Kozubowski, S.A. Hanson, J.E. Evans, W.L. Gladfelter, Chem. Mater., 7, 517, 1995

Identifiers

DOI

10.12693/APhysPolA.102.167