Epitaxial structures of self-organized, standing-up pentacene thin films studied by LEEM and STM
Epitaxial structures of self-organized, standing-up pentacene thin films studied by LEEM and STM
复制标题
DOI：
10.1016/j.susc.2006.12.064
复制
发表时间：
2007-03-01
期刊：
影响因子：
1.9
通讯作者：
Sakurai, T.
中科院分区：
文献类型：
--
作者：
Al-Mahboob, A.;Sadowski, J. T.;Sakurai, T.
用低能电子显微镜（LEEM）和扫描隧道显微镜（STM）原位研究了并五苯（Pn）薄膜的生长。在Bi（0001）/Si（111）模板上观察到非常低的Pn晶粒成核密度，导致形成直径超过几百微米的大的、单层高的Pn晶粒。我们确定，形成自组织的，站立的坑外延层稳定的衬底和Pn分子之间的弱相互作用，并通过存在的相称结构之间的倾斜Pn晶格和三角形衬底表面晶格。在Pn的沿着a轴和衬底表面晶格的一个基元矢量上发现了“点上线”可重构性。在Pn/Bi（0001）/Si（111）系统中，由于具有很强的“点上线”可结晶性，从第一层开始，生长出了块体状的外延薄膜。双胞胎的存在下，往往有一个镜像线平行于“点上线”匹配的方向，也已被检测到使用不对称暗场成像模式在LEEM实验，我们相信，这是第一个LEEM演示分子倾斜成像。(c)2006 Elsevier B. V.保留所有权利。
Growth of pentacene (Pn) thin films has been studied ill situ by means of low-energy electron microscopy (LEEM) and scanning tunneling microscopy (STM). A very low nucleation density of Pn grains has been observed on Bi(0001)/Si(111) template, resulting in formation of large, monolayer-high Pn grains with diameter exceeding several hundreds of micrometers. We determined that formation of self-organized, standing-up Pit epitaxial layers was stabilized by a weak interaction between the substrate and Pn molecules and by the presence of the commensurate structure between the oblique Pn lattice and trigonal substrate surface lattice. The 'point-on-line' commensurability has been found along a-axis of Pn and one of the primitive vectors of substrate surface lattice. Strong 'point-on-line' commensurability in Pn/Bi(0001)/Si(111) system resulted in a bulk-like epitaxial thin film growth, starting from the first layer. The presence of twins, often having a mirror line parallel to the direction of the 'point-on-line' matching, has been also detected using an asymmetric dark-field imaging mode in LEEM experiments, which, we believe, is the first LEEM demonstration of molecular tilt imaging. (c) 2006 Elsevier B.V. All rights reserved.