Sushko Peter V, Chambers Scott A
Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA.
Sci Rep. 2020 Aug 3;10(1):13028. doi: 10.1038/s41598-020-69658-9.
Internal electric fields that underpin functioning of multi-component materials systems and devices are coupled to structural and compositional inhomogeneities associated with interfaces in these systems. Hard-x-ray photoelectron spectroscopy is a valuable source of information on band-edge profiles, governed by the distribution of internal fields, deep inside semiconductor thin films and heterojunctions. However, extracting this information requires robust and physically meaningful decomposition of spectra into contributions from individual atomic planes. We present an approach that utilizes the physical requirements of a monotonic dependence of the built-in electrostatic potential on depth and continuity of the potential function and its derivatives. These constraints enable efficient extraction of band-edge profiles and allow one to capture details of the electronic structure, including determination of the signs and magnitudes of the band bending as well as the valence band offsets. The utility of this approach to generate quantitative insight into the electronic structure of complex materials is illustrated for epitaxial [Formula: see text] on intrinsic Si(001).
支撑多组分材料系统和器件功能的内部电场与这些系统中与界面相关的结构和成分不均匀性相耦合。硬X射线光电子能谱是获取有关能带边缘分布信息的宝贵来源，而能带边缘分布受半导体薄膜和异质结内部深处内场分布的支配。然而，提取此信息需要将光谱稳健且有物理意义地分解为各个原子平面的贡献。我们提出了一种方法，该方法利用内置静电势对深度的单调依赖性以及势函数及其导数的连续性的物理要求。这些约束条件能够有效提取能带边缘分布，并使人们能够捕捉电子结构的细节，包括确定能带弯曲的符号和大小以及价带偏移。通过在本征Si(001)上外延生长[化学式：见正文]，说明了这种方法对深入了解复杂材料电子结构的实用性。
