Role of step edges on the structure formation of α-6T on Ag(441)

SURFACE SCIENCE

卷:667

Article

Wagner, Thorsten¹  Fritz, Daniel Roman¹  Rudolfova, Zdena^1,2  Zeppenfeld, Peter¹ 

[1] Johannes Kepler Univ Linz, Inst Expt Phys, Altenberger Str 69, A-4040 Linz, Austria

[2] Brno Univ Technol, Tech 2896-2, Brno 61669, Czech Republic

关键词: alpha-sexithiophene;    Ag(441);    Vicinal surface;    PEEM;    STM;    Growth;   

DOI  :  10.1016/j.susc.2017.09.008

来源: Elsevier

【 摘 要 】

Controlling the orientation of organic molecules on surfaces is important in order to tune the physical properties of the organic thin films and, thereby, increase the performance of organic thin film devices. Here, we present a scanning tunneling microscopy (STM) and photoelectron emission microscopy (PEEM) study of the deposition of the organic dye pigment alpha-sexithiophene (alpha-6T) on the vicinal Ag(441) surface. In the presence of the steps on the Ag(441) surface, the alpha-6T molecules exclusively align parallel to the step edges oriented along the [1(1)over bar0]-direction of the substrate. The STM results further reveal that the adsorption of the alpha-6T molecules is accompanied by various restructuring of the substrate surface: Initially, the molecules prefer the Ag(551) building blocks of the Ag(441) surface. The Ag(551) termination of the terraces is then changed to a predominately Ag(331) one upon completion of the first alpha-6T monolayer. When closing the two layer thick wetting layer, the original ratio of Ag(331) and Ag(551) building blocks (approximate to 1:1) is recovered, but a phase separation into microfacets, which are composed either of Ag(331) or of Ag(551) building blocks, is found. (c) 2017 The Authors. Published by Elsevier B.V.

【 授权许可】

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