EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Nanoscale. 2012 Sep 28;4(19):5960-4. doi: 10.1039/c2nr31530k. Epub 2012 Aug 20.
Thin films of heavily B-doped nanocrystalline diamond (B:NCD) have been investigated by a combination of high resolution annular dark field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy performed on a state-of-the-art aberration corrected instrument to determine the B concentration, distribution and the local B environment. Concentrations of ~1 to 3 at.% of boron are found to be embedded within individual grains. Even though most NCD grains are surrounded by a thin amorphous shell, elemental mapping of the B and C signal shows no preferential embedding of B in these amorphous shells or in grain boundaries between the NCD grains, in contrast with earlier work on more macroscopic superconducting polycrystalline B-doped diamond films. Detailed inspection of the fine structure of the boron K-edge and comparison with density functional theory calculated fine structure energy-loss near-edge structure signatures confirms that the B atoms present in the diamond grains are substitutional atoms embedded tetrahedrally into the diamond lattice.
采用高分辨率环形暗场扫描透射电子显微镜和基于最先进的像差校正仪器的空间分辨电子能量损失光谱技术相结合，研究了重掺硼纳米晶金刚石（B:NCD）薄膜，以确定硼浓度、分布和局部硼环境。发现硼的浓度约为 1 至 3 原子百分比，嵌入在各个晶粒内。尽管大多数 NCD 晶粒都被一层薄的非晶壳包围，但硼和 C 信号的元素映射显示，硼并没有优先嵌入这些非晶壳或 NCD 晶粒之间的晶界中，这与之前对更宏观的超导多晶掺硼金刚石薄膜的研究结果不同。对硼 K 边精细结构的详细检查，并与基于密度泛函理论计算的精细结构能量损失近边结构特征进行比较，证实了存在于金刚石晶粒中的硼原子是嵌入在金刚石晶格中的替位原子。
