Ostwald ripening and flattening of epitaxial ZnO layers during in situ annealing in metalorganic vapor phase epitaxy
Ostwald ripening and flattening of epitaxial ZnO layers during in situ annealing in metalorganic vapor phase epitaxy
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DOI：
10.1063/1.1785871
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发表时间：
2004-08-30
影响因子：
4
通讯作者：
Diez, A
中科院分区：
文献类型：
--
作者：
Krost, A;Christen, J;Diez, A
ZnO薄膜生长在GaN/Si（111）衬底上的金属有机物气相外延在450 ℃，随后在原位退火900 ℃的时间范围从0到8分钟的外延层，其特征在于原子力显微镜，X射线衍射和阴极发光测量。所生长的ZnO层由[0001]取向的单晶的三维纳米尺度大小的簇组成。在退火的第一个1分钟期间，观察到由于材料的重新分布导致的表面平滑化，从而导致岛的数量和它们的高度两者的减少。经过2分钟的退火，表面形态已经完全改变，并转化为一个近二维的无簇表面。这种相变伴随着晶体和光学性质的强烈改善。这种效应归因于奥斯特瓦尔德熟化，随后晶体表面变平。(C)2004年，美国物理学会。
ZnO films were grown at 450degreesC by metalorganic vapor phase epitaxy on GaN/Si(111) substrate and subsequently annealed in situ at 900degreesC for times ranging from 0 to 8 min. The epitaxial layers were characterized by atomic force microscopy, x-ray diffraction, and cathodoluminescence measurements. The as-grown ZnO layers consist of three-dimensional nanoscale-sized clusters of [0001]-oriented monocrystallites. During the first 1 min of annealing, a surface smoothening due to a redistribution of material is observed leading to a decrease of both the island numbers and their heights. After 2 min of annealing, the surface morphology has completely changed and is transformed into a nearly two-dimensional cluster-free surface. This phase transition is accompanied by a strong improvement of the crystalline and optical properties. The effect is attributed to Ostwald ripening with a subsequent flattening of the crystal surface. (C) 2004 American Institute of Physics.