In this work, the dislocation etching pit morphology and etching kinetics on the A-{11$\overline{2}$0} plane of sapphire crystal (α-Al₂O₃) are studied experimentally. The results show that the etch pit exhibits a subrhombic 3D morphology, which is consistent with the atom arrangement symmetry of the A plane. Further analysis shows that the two adjacent sides of the rhombic etch pits correspond to the directions [3$\overline{3}$0$\overline{1}$] and [3$\overline{3}$02], respectively; both of them are in the atomic close-packing direction of A plane. The etch pits are controlled by a chemical reaction between Al₂O₃ and potassium hydroxide (KOH) with the reaction activation energy of 51.7 kJ mol⁻¹, which is developed in a manner of kinematic wave by the step moving with a constant speed.

中文翻译：

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蓝宝石晶体A面的位错蚀刻形貌

在这项工作中，A -{11上的位错蚀刻坑形态和蚀刻动力学$\overline{2}$对蓝宝石晶体 (α-Al ₂ O ₃ ) 的0} 面进行了实验研究。结果表明，蚀刻坑呈现亚菱形的3D形貌，与A面的原子排列对称性一致。进一步分析表明，菱形蚀刻坑的两个相邻边对应的方向[3$\overline{3}$0$\overline{1}$] 和 [3$\overline{3}$02]，分别；它们都在A平面的原子密堆积方向。蚀刻坑由Al ₂ O ₃与氢氧化钾(KOH)之间的化学反应控制，反应活化能为51.7 kJ mol ^-1，通过匀速步进运动以运动波的方式发展。