Laue x-ray diffraction photos are able to reveal the presences of twinning. Once a crystal is identified as twinned, what can the researcher do to de-twin the sample?
Hello Aaron,
Laue x-ray diffraction may not always be sufficient to reveal the twinning. You might have seen this paper (Journal of Crystal Growth 247 (2003) 457–466), which discuss the presence of twinning undetected by Laue x-ray and unsuccessful attempt to detwin crystal by uni-axial pressure. I have also discussed this in PHYSICAL REVIEW B 91, 054403 (2015).
Hello!
I hope that you are in semiconductor crystal growth field.
Twinning in bulk crystal is a big problem and to remove it another challenge to crystal growers. However, twin growth occurs during the thermal stress of container, therefore you should try to eliminate the thermal stress during crystal growth process itself. Only low angle twin might be eliminated on annealing, other wise not. If possible you may refer our publication, which is available on my ResearchGate site.
As an old-fashioned crystallographer, I would propose you to cut the crystal along the twinning plane that (if you have an idea of what it is) can be identified optically. Then you can work with a single crystal piece.
"Only low angle twin might be eliminated on annealing"
"Laue x-ray diffraction may not always be sufficient to reveal the twinning"
- Especially if you are still using the conventional photographic film.
- Using real time 2D detectors along with the rocking curve methodology it would be possible to detect any deviation from IDEAL crystal structure no matter how small. The key is to be able to detect even the minutest deviation from IDEAL Bragg condition.
- Modern tools and techniques in XRD will soon change the paradigm.
- See some examples below :-)
https://www.researchgate.net/post/What_is_the_best_way_to_interpret_REAL_TIME_3D_X_Y_o-2TH_o_ph_ch_reciprocal_space_relative_intensity_data_from_HRXRD_rocking_curve_analyses
https://www.flickr.com/photos/85210325@N04/11604959265/in/album-72157645018820696/
Ravi Ananth
"Only low angle twin might be eliminated on annealing"
1. How low an angle?
Answer : Twin angle < 15 degree, at present don't have reference to state here. But it is in the journals as well as books on crystal growth and morphology. I will try to report this information at the earliest.
Ravi Ananth
This is with reference to my previous answer, and hereby submitting the reference for low angle boundaries, which I have found in great difficulty.
Modern Semiconductor Physics Vol-4, Wolfgang Schroter, Gottingen, June -1991.
Chapter-7: Grain Boundaries in Semiconductor pp-323-378
Sub-chapters:
7.2.3.1- Low Angle Grain Boundaries
7.2.3.2- High Angle Grain Boundaries
I hope that this will help you.
Prin. (Dr) D B Gadkari
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