The interface of GaP(100) and H2O studied by photoemission and reflection anisotropy spectroscopy
The interface of GaP(100) and H2O studied by photoemission and reflection anisotropy spectroscopy
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DOI：
10.1088/1367-2630/15/10/103003
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发表时间：
2013-10-07
影响因子：
3.3
通讯作者：
Hannappel, Thomas
中科院分区：
文献类型：
--
作者：
May, Matthias M.;Supplie, Oliver;Hannappel, Thomas
我们研究了吸附的 H2O 与富 P 和富 Ga GaP(100) 表面的初始相互作用。通过金属有机气相外延制备原子级明确的表面，并将其无污染地转移到超高真空，在室温下水被吸附。最后，表面在气相环境中退火。在所有步骤中，通过原位反射各向异性光谱 (RAS) 监测对表面特性的影响。光电子能谱和低能电子衍射被应用于进一步的系统研究。 RA 光谱暴露至饱和后，富 Ga (2 x 4) 表面重建呈现出分子和解离吸附水混合物形式的亚单层覆盖。对于 p(2 x 2)/c(4 x 2) 富 P 表面重建，吸附时会形成新的 c(2 x 2) 超结构，并且与富 Ga 表面相比，吸附质的吸收显着减少。我们的研究结果表明，GaP(100) 的微观表面重建极大地影响了与水的初始界面形成机制，这可能有利于诸如水的设计。光电化学水分解装置。
We study the initial interaction of adsorbed H2O with P-rich and Ga-rich GaP(100) surfaces. Atomically well defined surfaces are prepared by metal-organic vapour phase epitaxy and transferred contamination-free to ultra-high vacuum, where water is adsorbed at room temperature. Finally, the surfaces are annealed in vapour phase ambient. During all steps, the impact on the surface properties is monitored with in situ reflection anisotropy spectroscopy (RAS). Photoelectron spectroscopy and low-energy electron diffraction are applied for further in system studies. After exposure up to saturation of the RA spectra, the Ga-rich (2 x 4) surface reconstruction exhibits a sub-monolayer coverage in form of a mixture of molecularly and dissociatively adsorbed water. For the p(2 x 2)/c(4 x 2) P- rich surface reconstruction, a new c(2 x 2) superstructure forms upon adsorption and the uptake of adsorbate is significantly reduced when compared to the Ga-rich surface. Our findings show that microscopic surface reconstructions of GaP(100) greatly impact the mechanism of initial interface formation with water, which could benefit the design of e.g. photoelectrochemical water splitting devices.