Chair of Physical Chemistry, Department of Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
Walter Schottky Institute and Physics Department, Technische Universität München, Am Coulombwall 4 85748 Garching, Germany.
J Chem Phys. 2017 Sep 28;147(12):124704. doi: 10.1063/1.4994141.
In this work, ethanol is used as a chemical probe to study the passivation of molecular beam epitaxy-grown GaN(0001) by surface oxidation. With a high degree of oxidation, no reaction from ethanol to acetaldehyde in temperature-programmed desorption experiments is observed. The acetaldehyde formation is attributed to a mechanism based on α-H abstraction from the dissociatively bound alcohol molecule. The reactivity is related to negatively charged surface states, which are removed upon oxidation of the GaN(0001) surface. This is compared with the GaO(2¯01) single crystal surface, which is found to be inert for the acetaldehyde production. These results offer a toolbox to explore the surface chemistry of nitrides and oxynitrides on an atomic scale and relate their intrinsic activity to systems under ambient atmosphere.
在这项工作中，我们使用乙醇作为化学探针来研究分子束外延生长 GaN(0001) 表面氧化的钝化。在高度氧化的情况下，在程序升温脱附实验中，没有观察到乙醇到乙醛的反应。乙醛的形成归因于一种基于从离解结合的醇分子中α-H 提取的机制。这种反应性与带负电荷的表面态有关，而这些表面态在 GaN(0001)表面氧化时被去除。这与 GaO(2¯01)单晶表面进行了对比，发现后者对于乙醛的生成是惰性的。这些结果为在原子尺度上探索氮化物和氧氮化物的表面化学提供了一个工具包，并将它们的固有活性与其在环境气氛下的系统联系起来。
