Characterizing the CH 3 SSCH 3 –Au(111) System From Single Molecules To Full Surface Coverage: A Scanning Tunneling Microscopy Study
Characterizing the CH 3 SSCH 3 –Au(111) System From Single Molecules To Full Surface Coverage: A Scanning Tunneling Microscopy Study
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从单分子到全表面覆盖的 CH 3 SSCH 3 – Au(111) 系统表征：扫描隧道显微镜研究
DOI：
10.1021/acs.jpcc.1c06780
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Hipps, K. W.
中科院分区：
文献类型：
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作者：
Zhang, Yi C.;Lee, David Y.;Hipps, K. W.
在温度低于130 K的条件下，用亚纳米分辨率分析了二甲基二硫化物在Au（111）表面的吸附过程。我们报道了两个温度依赖的吸附研究，以达到CH3SSCH3-Au（111）体系的完全不同的表面形态。从低温低覆盖的冷合成方法开始，STM图像显示了Au（111）人字形重建表面特定区域的优先吸附。然而，在饱和表面覆盖下，80 K退火会导致ch3ssch3外延单层的自组装，这受到人字形重构的各向异性性质的影响。相反，在80 K及以上的温度下沉积ch3ssch3会导致ch3ssch3和解离的sch3碎片同时在表面吸附。沉积在80 K Au表面的ch3ssch3的饱和覆盖不会产生自组装的单层。DFT计算用于提供对这两种合成方法的见解，这些方法导致CH3SSCH3-Au（111）体系中表面形貌的差异。我们还证明了低温下尖端诱导和紫外线诱导的ch3ssch3解离。我们发现紫外产生的碎片的空间分布明显大于尖端电子产生的碎片的空间分布，表明这两个过程的不同机制。
The adsorption process of dimethyl disulfide onto the Au(111) surface was resolved with subnanometer resolution at temperatures below 130 K. We report two temperature dependent adsorption studies to reach totally different surface morphologies for this CH3SSCH3–Au(111) system. Starting with a cold-synthesis approach at low-temperature and low coverage, the STM images reveal preferential adsorption at specific regions on the Au(111) herringbone reconstructed surface. However, at saturated surface coverage, annealing at 80 K leads to self-assembly of an epitaxial monolayer of CH3SSCH3that is influenced by the anisotropic nature of the herringbone reconstruction. In contrast, depositing CH3SSCH3at 80 K and above leads to simultaneous adsorption of CH3SSCH3and dissociated SCH3fragments on the surface. Saturation coverage of CH3SSCH3deposited on an 80 K Au surfaces produces no self-assembled monolayer. DFT calculations are used to provide insights into these two synthesis methods that lead to a discrepancy in surface morphology in the CH3SSCH3–Au(111) system. We also demonstrate both tip induced and UV induced dissociation of CH3SSCH3at cryogenic temperatures. We find that the spatial distribution of the UV produced fragments is significantly greater than that of those produced by tip electrons indicating differing mechanisms for the two processes.