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Passivation of surface states of α-Fe2O3(0001) surface by deposition of Ga2O3 overlayers: A density functional theory study
The Journal of Chemical Physics ( IF 3.1 ) Pub Date : 2016-03-01 14:14:35 , DOI: 10.1063/1.4942655 Kanchan Ulman 1 , Manh-Thuong Nguyen 1 , Nicola Seriani 1 , Ralph Gebauer 1
The Journal of Chemical Physics ( IF 3.1 ) Pub Date : 2016-03-01 14:14:35 , DOI: 10.1063/1.4942655 Kanchan Ulman 1 , Manh-Thuong Nguyen 1 , Nicola Seriani 1 , Ralph Gebauer 1
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There is a big debate in the community regarding the role of surface states of hematite in the photoelectrochemical water splitting. Experimental studies on non-catalytic overlayers passivating the hematitesurface states claim a favorable reduction in the overpotential for the water splitting reaction. As a first step towards understanding the effect of these overlayers, we have studied the system Ga2O3 overlayers on hematite (0001) surfaces using first principles computations in the PBE+U framework. Our computations suggest that stoichiometric terminations of Ga2O3 overlayers are energetically more favored than the bare surface, at ambient oxygen chemical potentials. Energetics suggest that the overlayers prefer to grow via a layer-plus-island (Stranski–Krastanov) growth mode with a critical layer thickness of 1–2 layers. Thus, a complete wetting of the hematitesurface by an overlayer of gallium oxide is thermodynamically favored. We establish that the effect of deposition of the Ga2O3 overlayers on the bare hematitesurface is to passivate the surface states for the stoichiometric termination. For the oxygen terminated surface which is the most stable termination under photoelectrochemical conditions, the effect of deposition of the Ga2O3 overlayer is to passivate the hole-trapping surface state.
中文翻译：
通过沉积Ga2O3叠层钝化α-Fe2O3（0001）表面的表面态：密度泛函理论研究
关于赤铁矿的表面状态在光电化学水分解中的作用，社会上存在着很大的争论。对非催化覆盖层钝化赤铁矿表面态的实验研究表明，有利于减少水分解反应的过电势。作为了解这些叠加器效果的第一步，我们使用PBE + U框架中的第一原理计算研究了赤铁矿（0001）表面上的Ga 2 O 3叠加器系统。我们的计算表明，Ga 2 O 3的化学计量终止在环境氧化学势下，与裸露的表面相比，能量覆盖层在能量上更受青睐。高能技术表明，叠层器倾向于通过临界岛厚度为1-2层的“层加岛”（Stranski–Krastanov）生长模式进行生长。因此，热力学上有利于用氧化镓覆盖层完全浸润赤铁矿表面。我们确定，在裸露的赤铁矿表面沉积Ga 2 O 3叠层的作用是钝化化学计量终止的表面状态。对于在光电化学条件下最稳定的端接氧的表面，Ga 2 O 3沉积的影响 覆盖层是用来钝化空穴俘获表面的状态。
更新日期：2016-03-02
中文翻译：
通过沉积Ga2O3叠层钝化α-Fe2O3（0001）表面的表面态：密度泛函理论研究
关于赤铁矿的表面状态在光电化学水分解中的作用，社会上存在着很大的争论。对非催化覆盖层钝化赤铁矿表面态的实验研究表明，有利于减少水分解反应的过电势。作为了解这些叠加器效果的第一步，我们使用PBE + U框架中的第一原理计算研究了赤铁矿（0001）表面上的Ga 2 O 3叠加器系统。我们的计算表明，Ga 2 O 3的化学计量终止在环境氧化学势下，与裸露的表面相比，能量覆盖层在能量上更受青睐。高能技术表明，叠层器倾向于通过临界岛厚度为1-2层的“层加岛”（Stranski–Krastanov）生长模式进行生长。因此，热力学上有利于用氧化镓覆盖层完全浸润赤铁矿表面。我们确定，在裸露的赤铁矿表面沉积Ga 2 O 3叠层的作用是钝化化学计量终止的表面状态。对于在光电化学条件下最稳定的端接氧的表面，Ga 2 O 3沉积的影响 覆盖层是用来钝化空穴俘获表面的状态。
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