On the nucleation and initial film growth of rod-like organic molecules

SURFACE SCIENCE

卷:652

Article

Winkler, Adolf¹ 

[1] Graz Univ Technol, Inst Solid State Phys, Petersgasse 16, A-8010 Graz, Austria

关键词: Organic molecules;    Thin films;    Nucleation;    Critical island size;   

DOI  :  10.1016/j.susc.2016.02.015

来源: Elsevier

【 摘 要 】

In this article, some fundamental topics related to the initial steps of organic film growth are reviewed. General conclusions will be drawn based on experimental results obtained for the film formation of oligophenylene and pentacene molecules on gold and mica substrates. Thin films were prepared via physical vapor deposition under ultrahigh-vacuum conditions and characterized in-situ mainly by thermal desorption spectroscopy, and ex-situ by X-ray diffraction and atomic force microscopy. In this short review article the following topics will be discussed: What are the necessary conditions to form island-like films which are either composed of flat-lying or of standing molecules? Does a wetting layer exist below and in between the islands? What is the reason behind the occasionally observed bimodal island size distribution? Can one describe the nucleation process with the diffusion-limited aggregation model? Do the impinging molecules directly adsorb on the surface or rather via a hot-precursor state? Finally, it will be described how the critical island size can be determined by an independent measurement of the deposition rate dependence of the island density and the capture-zone distribution via a universal relationship. (C) 2016 The Author. Published by Elsevier B.V.

【 授权许可】

Free