The influence of carbon on the adsorption/desorption kinetics and monolayer formation of p-quaterphenyl on Au(111)
The influence of carbon on the adsorption/desorption kinetics and monolayer formation of p-quaterphenyl on Au(111)
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DOI：
10.1016/j.susc.2004.10.044
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发表时间：
2005-01-10
期刊：
影响因子：
1.9
通讯作者：
Winkler, A
中科院分区：
文献类型：
--
作者：
Müllegger, S;Winkler, A
利用热脱附谱（TDS）、X射线光电子能谱（XPS）和微通道板低能电子衍射（MCP-LEED）研究了超高真空条件下表面碳对在Au（111）表面生长的高度规则的对四联苯（4 P）单层和多层薄膜的影响。一个小的碳预覆盖0.03单层（ML），通过钝化Au表面缺陷，提高了吸附的4P分子相对于清洁表面的表面迁移率。这使得即使在93 K的低衬底温度下也能够生长高度结晶的4P膜。否则，热稳定的单层结构是相同的C-自由表面上，即由交替的边缘/面包装，躺分子。在0.15 ML C覆盖的Au（111）表面上生长的第一个V单层的结构是不同的。只有边缘取向的分子才能容纳在相应的表面晶胞中。在C覆盖率为0.5ML的第一个4P单层是无序的，而对于更高的覆盖率的高度结晶结构与直立的分子被采用。根据薄膜生长过程中的衬底温度，表面碳导致4P薄膜的不同润湿行为，导致不同的介观薄膜形态。(C)2004 Elsevier B.V.保留所有权利。
The influence of surface carbon on the formation of highly regular thin films of p-quaterphenyl (4P) grown on a Au(111) surface has been investigated in the mono- and multilayer regime by thermal desorption spectroscopy (TDS), X-ray photoelectron spectroscopy (XPS) and micro-channelplate low energy electron diffraction (MCP-LEED) under UHV conditions. A small carbon pre-coverage of 0.03 monolayers (ML) improves the surface mobility of adsorbed 4P molecules with respect to the clean surface by passivating Au surface defects. This enables a highly crystalline 4P film growth even at a low substrate temperature of 93 K. Otherwise, the thermodynamically stable monolayer structure is identical to that on the C-free surface, namely consisting of alternating edge/face packed, lying molecules. The structure of the first V monolayer grown on a 0.15 ML C covered Au(111) surface is different. Only edge-on oriented molecules accommodate in the corresponding surface unit cell. At a C coverage of 0.5ML the first 4P monolayer is disordered, whereas for higher coverages a highly crystalline structure with upright standing molecules is adopted. Depending on the substrate temperature during film growth the surface carbon causes a different wetting behaviour of the 4P films, resulting in a different mesoscopic film morphology. (C) 2004 Elsevier B.V. All rights reserved.