Polarization-induced charge carrier separation in polar and nonpolar grown GaN quantum dots
Polarization-induced charge carrier separation in polar and nonpolar grown GaN quantum dots
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极性和非极性生长的 GaN 量子点中极化引起的载流子分离
DOI：
10.1063/1.3246864
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发表时间：
2009
影响因子：
3.2
通讯作者：
J. Neugebauer
中科院分区：
文献类型：
--
作者：
O. Marquardt;T. Hickel;J. Neugebauer
我们对极性和非极性表面上生长的纤锌矿 GaN/AlN 量子点进行了系统研究。为此，在八带 k⋅p 模型中采用了实验观察到的量子点几何形状。发现非极性量子点中由于极化电位而导致的电子和空穴的空间分离比极性生长的量子点大得多。为了提高电子空穴重叠从而提高复合率，我们改变了非极性量子点的形状、尺寸和周期性排列。我们观察到尺寸减小的非极性量子点中电荷载流子重叠的最强改善。如果尺寸减小到文献中最近报道的尺寸的 60% 以下，则这种增加显然比极性量子点更明显，这表明较小的非极性量子点的复合率要好得多。
We have performed systematic studies of wurtzite GaN/AlN quantum dots grown on polar and nonpolar surfaces. For this purpose, experimentally observed quantum dot geometries have been employed within an eight-band k⋅p model. The spatial separation of electrons and holes due to polarization potentials is found to be much larger in nonpolar than in polar grown quantum dots. In order to improve the electron-hole overlap and thus the recombination rates, we have varied the shape, size, and the periodic arrangement of nonpolar quantum dots. We observed the strongest improvement of the charge carrier overlap in nonpolar quantum dots that have a reduced dimension. If the size is reduced below 60% of the dimensions reported recently in literature, this increase is clearly more pronounced than for the polar quantum dots, indicating much better recombination rates in smaller nonpolar quantum dots.