Local boron environment in B-doped nanocrystalline diamond films.
Local boron environment in B-doped nanocrystalline diamond films.
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DOI：
10.1039/c2nr31530k
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发表时间：
2012-09
期刊：
影响因子：
6.7
通讯作者：
S. Turner;Ying‐gang Lu;S. Janssens;F. Da Pieve;D. Lamoen;J. Verbeeck;K. Haenen;P. Wagner;G. van Tendeloo
中科院分区：
文献类型：
--
作者：
S. Turner;Ying‐gang Lu;S. Janssens;F. Da Pieve;D. Lamoen;J. Verbeeck;K. Haenen;P. Wagner;G. van Tendeloo
采用高分辨环形暗场扫描透射电子显微镜和空间分辨电子能量损失谱相结合的方法研究了重掺硼纳米金刚石（B：NCD）薄膜中B的浓度、分布和局部B环境。浓度约为1至3 at.%硼被发现是嵌入在个别晶粒。尽管大多数NCD晶粒被薄的非晶壳包围，但B和C信号的元素映射显示B在这些非晶壳中或在NCD晶粒之间的晶界中没有优先嵌入，这与更宏观的超导多晶B掺杂金刚石膜的早期工作相反。详细检查硼K边缘的精细结构，并与密度泛函理论计算的精细结构能量损失近边缘结构特征的比较，证实了金刚石晶粒中存在的B原子是四面体嵌入金刚石晶格中的替代原子。
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.