Hello all,
I got asymmetric peaks in the XRD of the InGaN thin films that were grown on the sapphire substrate and I am trying to understand the reason for this behavior.
Could anyone help me with this?
Hi Kiran, What kind of scans have you measured? In case of radial scan (om/2Th), the asymmetry of peaks could be because of: a) phase separation; b) composition/strain gradient etc.
Hello Andrian, thanks for your response. Its om/2Th scan only.. I believe It could be due to the composition/strain gradient as there no secondary peak observed in PL.. Any further explanation with suitable references would be highly appreciated..
If there is no any little satellite peak, then lattice distortion could be one of the reasons, but you should also consider alignment of your beam with sample.
Dear Kirian
In general - there is a lot of literature on the growth of InGaN layers on GaN / Szafir substrates (0001). The growth by MBE and MOCVD techniques are also different. However, I share the view of Adrian Kuchczuk that you are probably observing the effects of strain gradient. I send you an interesting artice for example: 1) Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy Journal of Applied Physics 118, 155301 (2015); https://doi.org/10.1063/1.4933276 2) Journal of Electronic Materials, April 2001, Volume 30, Issue 4, pp. 439–444 | Relaxation of InGaN thin layers observed by X-ray and transmission electron microscopy studies
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