Analysis of the modified williamson-hall plot of non-polar a-plane GaN films
Analysis of the modified williamson-hall plot of non-polar a-plane GaN films
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DOI：
10.3938/jkps.62.601
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发表时间：
2013-03
影响因子：
0.6
通讯作者：
Jihoon Kim;Y. Seo;S. Hwang;Soohwan Jang;K. Baik
中科院分区：
文献类型：
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作者：
Jihoon Kim;Y. Seo;S. Hwang;Soohwan Jang;K. Baik
为了更好地理解x射线束内方向的各向异性峰展宽，我们报道了非极性平面GaN （a-GaN）薄膜的Williamson-Hall （W-H）图分析。不同角度x射线摇摆曲线对称反射的半最大值全宽度（FWHM）值清楚地显示了其结构性能的各向异性行为。对对称和反射的修正W-H图分析表明，拼接块沿c轴方向高度伸长。非对称几何结构中n阶反射峰宽度的W-H图（φ = 0°）可以提供有关a-GaN薄膜微观结构状态的有用信息。我们发现，对于具有高结晶质量的a- gan薄膜，可以获得~ 285 nm的相干散射长度。我们注意到，从W-H分析中获得的相干散射长度可以显着低估非极性a-GaN薄膜的基面层错密度。
We report on the Williamson-Hall (W-H) plot analysis of non-polar a-plane GaN (a-GaN) films for a better understanding of the anisotropic peak broadening with X-ray in-beam direction. The full width at half maximum (FWHM) values of the symmetric reflections of the X-ray rocking curves at different angles phi for the a-GaN film clearly show the anisotropic behavior of its structural property. A modified W-H plot analysis of the symmetric and reflections shows that the mosaic blocks are highly elongated along the c-axis direction. The W-H plots of the peak widths from the nth order reflections in the asymmetric geometry with an angle chi of 30° (ϕ = 0°) can provide quite useful information on the microstructural state of a-GaN films. We found that a coherent scattering length of ∼285 nm could be obtained for an a-GaN film with high crystalline quality. We note that the coherent scattering lengths obtained from W-H analyses can significantly underestimate the density of basal-plane stacking faults for nonpolar a-GaN films.