Turner S, Idrissi H, Sartori A F, Korneychuck S, Lu Y-G, Verbeeck J, Schreck M, Van Tendeloo G
EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Universität Augsburg, Institut für Physik, D-86135 Augsburg, Germany.
Nanoscale. 2016 Jan 28;8(4):2212-8. doi: 10.1039/c5nr07535a.
A thin film of heavily B-doped diamond has been grown epitaxially by microwave plasma chemical vapor deposition on an undoped diamond layer, on top of a Ir/YSZ/Si(001) substrate stack, to study the boron segregation and boron environment at the dislocations present in the film. The density and nature of the dislocations were investigated by conventional and weak-beam dark-field transmission electron microscopy techniques, revealing the presence of two types of dislocations: edge and mixed-type 45° dislocations. The presence and distribution of B in the sample was studied using annular dark-field scanning transmission electron microscopy and spatially resolved electron energy-loss spectroscopy. Using these techniques, a segregation of B at the dislocations in the film is evidenced, which is shown to be intermittent along the dislocation. A single edge-type dislocation was selected to study the distribution of the boron surrounding the dislocation core. By imaging this defect at atomic resolution, the boron is revealed to segregate towards the tensile strain field surrounding the edge-type dislocations. An investigation of the fine structure of the B-K edge at the dislocation core shows that the boron is partially substitutionally incorporated into the diamond lattice and partially present in a lower coordination (sp(2)-like hybridization).
通过微波等离子体化学气相沉积法，在Ir/YSZ/Si(001)衬底堆叠顶部的未掺杂金刚石层上外延生长了一层重硼掺杂的金刚石薄膜，以研究薄膜中存在的位错处的硼偏析和硼环境。通过常规和弱束暗场透射电子显微镜技术研究了位错的密度和性质，发现存在两种类型的位错：刃型位错和45°混合型位错。使用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研究了样品中硼的存在和分布。利用这些技术，证明了薄膜中位错处存在硼偏析，且沿位错呈间歇性分布。选择单个刃型位错来研究位错核心周围硼的分布。通过在原子分辨率下对该缺陷成像，发现硼向刃型位错周围的拉伸应变场偏析。对位错核心处B-K边的精细结构研究表明，硼部分以替代方式掺入金刚石晶格，部分以较低配位（类似sp(2)杂化）形式存在。
