Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
Nano Lett. 2012 May 9;12(5):2199-204. doi: 10.1021/nl203872q. Epub 2012 Apr 18.
We demonstrate the nucleation of self-assembled, epitaxial GaN nanowires (NWs) on (111) single-crystalline diamond without using a catalyst or buffer layer. The NWs show an excellent crystalline quality of the wurtzite crystal structure with m-plane faceting, a low defect density, and axial growth along the c-axis with N-face polarity, as shown by aberration corrected annular bright-field scanning transmission electron microscopy. X-ray diffraction confirms single domain growth with an in-plane epitaxial relationship of (10 ̅10)(GaN) [parallel] (01 ̅1)(Diamond) as well as some biaxial tensile strain induced by thermal expansion mismatch. In photoluminescence, a strong and sharp excitonic emission reveals excellent optical properties superior to state-of-the-art GaN NWs on silicon substrates. In combination with the high-quality diamond/NW interface, confirmed by high-resolution transmission electron microscopy measurements, these results underline the potential of p-type diamond/n-type nitride heterojunctions for efficient UV optoelectronic devices.
我们展示了在（111）单晶金刚石上无催化剂或缓冲层自组装、外延 GaN 纳米线（NWs）的成核。通过像差校正环形明场扫描透射电子显微镜观察，NWs 显示出具有纤锌矿晶体结构的极好的晶体质量、低缺陷密度以及沿 c 轴的轴向生长和 N 面极性，m 面的面取。X 射线衍射证实了具有（10 ̅10）（GaN）[平行]（01 ̅1）（金刚石）面内外延关系的单畴生长，以及热膨胀失配引起的一些双轴拉伸应变。在光致发光中，强而尖锐的激子发射显示出优异的光学性能，优于硅衬底上的 GaN NWs 的现有技术水平。结合高分辨率透射电子显微镜测量所证实的高质量金刚石/NW 界面，这些结果强调了高效 UV 光电设备中 p 型金刚石/n 型氮化物异质结的潜力。
