In situ a-plane GaN nanodots were formed on r-plane sapphire substrates to obtain a-plane GaN layers by using hydride vapor phase epitaxy (HVPE). The size and density of the GaN nanodots influence the juncture of the 2D growth of a-plane GaN, thus determining the density of threading dislocations and stacking faults as well as the surface morphology in growing a-plane GaN layers. Faster agglomeration in a-plane GaN layers via GaN nanodots with small size and high density leads to a decrease in the density of threading dislocations. A higher number of grain boundaries formed by nanodots with small size and high density are also responsible for a reduction in the number of stacking faults. Furthermore, we infer that the reduced atomic migration length difference of Ga and N along the c-axis and m-axis directions in GaN nanodots formed at low growth temperatures improved the surface morphology of a-plane GaN layers via the formation of a-plane GaN islands with an isotropic shape. We believe that this approach will provide a simple and efficient way to control the structural defects and surface undulations of a-plane GaN layers without any complex processes or additional expense.

中文翻译：

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的形成原位HVPE一个面GaN纳米点：上的结构特性影响一个面GaN模板†

通过使用氢化物​​气相外延（HVPE），在r面蓝宝石衬底上原位形成a面GaN纳米点以获得a面GaN层。GaN纳米点的大小和密度会影响a平面GaN二维生长的结点，从而确定生长a平面GaN层时的螺纹位错和堆叠缺陷的密度以及表面形态。在更快的凝聚一个面GaN层通过具有小尺寸和高密度的GaN纳米点导致穿线位错的密度降低。由具有小尺寸和高密度的纳米点形成的更多数量的晶界也负责减少堆垛层错的数量。此外，我们推断，在低生长温度下形成的GaN纳米点中，Ga和N沿c轴和m轴方向的原子迁移长度差减小，从而通过a平面的形成改善了a平面GaN层的表面形态。具有各向同性形状的GaN岛。我们认为，这种做法将提供一个简单而有效的方法来控制的结构缺陷和表面起伏一个平面GaN层，而无需任何复杂的过程或额外的费用。