High Aspect Ratio GaN Fin Microstructures with Nonpolar Sidewalls by Continuous Mode Metalorganic Vapor Phase Epitaxy
High Aspect Ratio GaN Fin Microstructures with Nonpolar Sidewalls by Continuous Mode Metalorganic Vapor Phase Epitaxy
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DOI：
10.1021/acs.cgd.5b01598
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发表时间：
2016-03-01
影响因子：
3.8
通讯作者：
Waag, Andreas
中科院分区：
文献类型：
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作者：
Hartmann, Jana;Steib, Frederik;Waag, Andreas
具有高纵横比的三维GaN微米和纳米棒最近在发光二极管研究中获得了极大的兴趣，这是由于它们降低的缺陷密度、它们的非极性侧壁以及它们增加的有源区域。在这里，我们提出了一种替代的几何形状的高纵横比的三维纳米结构：垂直站立的GaN“墙”，所谓的GaN鳍。具有高纵横比，这些GaN鳍表现出与上述棒对应物相同的有趣特性。除此之外，由于它们的几何形状，相应的材料分析和器件处理可以预期不那么复杂。我们能够证明这些鳍片的连续模式金属有机气相外延的高度可重复的选择性区域生长。在生长初期，生长速度高达22.8 μ m/h，鳍高可达50 μ m以上（纵横比接近14）。侧壁是光滑的非极性a平面，由于与棒相比缺少量子限制斯塔克效应和较少的边缘效应，适合于光电器件。我们调查的影响，图案的方向和几何形状上的鳍形态。此外，硅烷流的影响，这是已知的，以提高垂直生长速率，和其他生长参数进行了系统的探索。
Three-dimensional GaN micro- and nanorods with a high aspect ratio have recently gained substantial interest in light-emitting diode research, due to their reduced defect density, their nonpolar sidewalls, and their increased active area. Here, we present an alternative geometry for high aspect ratio three-dimensional nanostructures: vertically standing GaN "walls", so-called GaN fins. With high aspect ratios, these GaN fins exhibit the same interesting characteristics as their rod counterparts mentioned above. Beyond that, because of their geometry, the respective material analysis and device processing can be expected to be less complex. We are able to demonstrate the highly reproducible selective area growth of these fins by continuous mode metalorganic vapor phase epitaxy. Fin heights of more than 50 mu m (aspect ratios of nearly 14) could be achieved, and growth rates are as high as 22.8 mu m/h in the beginning of the growth. The sidewalls are smooth nonpolar a-planes, suitable for optoelectronic devices due to the missing quantum-confined Stark effect and less edge effects compared to rods. We investigate the influence of pattern orientation and geometry on the fin morphology. Moreover, the influence of silane flow, which is known to enhance the vertical growth rate, and other growth parameters are systematically explored.