Dual-polarity GaN micropillars grown by metalorganic vapour phase epitaxy: Cross-correlation between structural and optical properties
Dual-polarity GaN micropillars grown by metalorganic vapour phase epitaxy: Cross-correlation between structural and optical properties
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DOI：
10.1063/1.4870950
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发表时间：
2014-04-21
影响因子：
3.2
通讯作者：
Zuniga-Perez, J.
中科院分区：
文献类型：
--
作者：
Coulon, P. M.;Mexis, M.;Zuniga-Perez, J.
研究了用金属有机气相外延技术在(0001)蓝宝石衬底上自组装无催化剂GaN微柱。透射式电子显微镜以及KOH蚀刻显示，在每个单个微柱内系统地存在两个极性相反的区域。对初始生长阶段的分析表明，这种双极性起源于微柱/衬底界面，即在微柱形核期间，并沿微柱传播。此外，在线/衬底界面上也会产生位错，但在几百纳米后发生弯曲。这导致了几十微米长的微柱是无位错的。空间分辨阴极发光和显微光致发光在每个极性域的光学性质上有很大的差异，这表明不同的极性存在不同的杂质/掺杂/空位掺入。(C)2014 AIP出版有限责任公司。
Self-assembled catalyst-free GaN micropillars grown on (0001) sapphire substrates by metal organic vapor phase epitaxy are investigated. Transmission electron microscopy, as well as KOH etching, shows the systematic presence of two domains of opposite polarity within each single micropillar. The analysis of the initial growth stages indicates that such double polarity originates at the micropillar/substrate interface, i.e., during the micropillar nucleation, and it propagates along the micropillar. Furthermore, dislocations are also generated at the wire/substrate interface, but bend after several hundreds of nanometers. This leads to micropillars several tens of micrometers in length that are dislocation-free. Spatially resolved cathodoluminescence and microphotoluminescence show large differences in the optical properties of each polarity domain, suggesting unequal impurity/dopant/vacancy incorporation depending on the polarity. (C) 2014 AIP Publishing LLC.