Water adsorption on the P-rich GaP(100) surface: optical spectroscopy from first principles
Water adsorption on the P-rich GaP(100) surface: optical spectroscopy from first principles
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DOI：
10.1088/1367-2630/aaaf38
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发表时间：
2018-03-29
影响因子：
3.3
通讯作者：
Sprik, Michiel
中科院分区：
文献类型：
--
作者：
May, Matthias M.;Sprik, Michiel
水与半导体的接触通常会通过氧化或腐蚀过程改变其表面电子结构。对表面结构的详细了解甚至控制是非常必要的，因为它会影响从气体传感到能量转换应用的光电器件的性能。这也是基于密度泛函理论对与电解质接触的电子结构进行建模的先决条件。富磷的 GaP(100) 表面在与气相水接触方面非常出色，因为它会经历表面重排，但不会氧化。我们通过理论上推导的反射各向异性光谱（RAS）研究与水接触的表面的潜在变化。我们的结果与实验的比较表明，表面上水诱导的富氢相与实验的边界条件兼容，再现了光谱。我们讨论了潜在的反应路径，包括水增强的表面氢迁移率。我们的结果还表明，解释实验特征所需的计算 RAS 对于与水双层接触的 GaP 是可行的。在这里，RAS 对表面电场敏感，而表面电场是亥姆霍兹层的重要组成部分。这为未来 RAS 在半导体-电解质界面的研究铺平了道路。
The contact of water with semiconductors typically changes its surface electronic structure by oxidation or corrosion processes. A detailed knowledge-or even control of-the surface structure is highly desirable, as it impacts the performance of opto-electronic devices from gas-sensing to energy conversion applications. It is also a prerequisite for density functional theory-based modelling of the electronic structure in contact with an electrolyte. The P-rich GaP(100) surface is extraordinary with respect to its contact with gas-phase water, as it undergoes a surface reordering, but does not oxidise. We investigate the underlying changes of the surface in contact with water by means of theoretically derived reflection anisotropy spectroscopy (RAS). A comparison of our results with experiment reveals that a water-induced hydrogen-rich phase on the surface is compatible with the boundary conditions from experiment, reproducing the optical spectra. We discuss potential reaction paths that comprise a water-enhanced hydrogen mobility on the surface. Our results also show that computational RAS-required for the interpretation of experimental signatures-is feasible for GaP in contact with water double layers. Here, RAS is sensitive to surface electric fields, which are an important ingredient of the Helmholtz-layer. This paves the way for future investigations of RAS at the semiconductor-electrolyte interface.