Crystallography and Structural Physics, University of Erlangen-Nürnberg , 91058 Erlangen, Germany.
ACS Nano. 2014 Dec 23;8(12):12676-81. doi: 10.1021/nn5056223. Epub 2014 Nov 21.
X-ray reflectivity measurements of increasingly more complex interfaces involving silicon (001) substrates reveal the existence of a thin low-density layer intruding between the single-crystalline silicon and the amorphous native SiO2 terminating it. The importance of accounting for this layer in modeling silicon/liquid interfaces and silicon-supported monolayers is demonstrated by comparing fits of the measured reflectivity curves by models including and excluding this layer. The inclusion of this layer, with 6-8 missing electrons per silicon unit cell area, consistent with one missing oxygen atom whose bonds remain hydrogen passivated, is found to be particularly important for an accurate and high-resolution determination of the surface normal density profile from reflectivities spanning extended momentum transfer ranges, now measurable at modern third-generation synchrotron sources.
X 射线反射率测量越来越复杂的涉及硅（001）衬底的界面表明，在单晶硅和终止它的非晶态本征 SiO2 之间存在一个薄的低密度层。通过比较包括和不包括这个层的模型对测量反射率曲线的拟合，证明了在建模硅/液体界面和硅支撑的单层时考虑这个层的重要性。这个层包含每硅单位面积 6-8 个缺失的电子，与一个缺失的氧原子一致，其键仍然被氢钝化，对于从跨越扩展动量转移范围的反射率准确和高分辨率地确定表面法向密度分布特别重要，现在可以在现代第三代同步加速器源中测量到。
