†IV. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
‡Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, 39106 Magdeburg, Germany.
Nano Lett. 2015 Aug 12;15(8):5105-9. doi: 10.1021/acs.nanolett.5b01278. Epub 2015 Aug 3.
Selective area growth has been applied to fabricate a homogeneous array of GaN nanocolumns (NC) with high crystal quality. The structural and optical properties of single NCs have been investigated at the nanometer-scale by transmission electron microscopy (TEM) and highly spatially resolved cathodoluminescence (CL) spectroscopy performed in a scanning transmission electron microscope (STEM) at liquid helium temperatures. TEM cross-section analysis reveals excellent structural properties of the GaN NCs. Sporadically, isolated basal plane stacking faults (BSF) can be found resulting in a remarkably low BSF density in the almost entire NC ensemble. Both, defect-free NCs and NCs with few BSFs have been investigated. The low defect density within the NCs allows the characterization of individual BSFs, which is of high interest for studying their optical properties. Direct nanometer-scale correlation of the CL and STEM data clearly exhibits a spatial correlation of the emission at 360.6 nm (3.438 eV) with the location of basal plane stacking faults of type I1.
选择区域生长已被应用于制造具有高质量晶体的 GaN 纳米柱（NC）的均匀阵列。通过透射电子显微镜（TEM）和在扫描透射电子显微镜（STEM）中在液氦温度下进行的高空间分辨率的阴极发光（CL）光谱研究，在纳米尺度上研究了单个 NC 的结构和光学性质。TEM 横截面分析揭示了 GaN NC 的优异结构性质。偶尔，可以发现孤立的基面堆垛层错（BSF），导致几乎整个 NC 集合中的 BSF 密度显着降低。已经研究了无缺陷的 NC 和具有少量 BSF 的 NC。NC 内的低缺陷密度允许对单个 BSF 进行表征，这对于研究它们的光学性质非常重要。CL 和 STEM 数据的直接纳米级相关清楚地显示了在 360.6nm（3.438eV）处的发射与 I1 型基面堆垛层错位置的空间相关性。
