Growth of pentacene on alpha-Al2O3(0001) studied by in situ optical spectroscopy
Growth of pentacene on alpha-Al2O3(0001) studied by in situ optical spectroscopy
复制标题
原位光谱研究并五苯在 α-Al2O3(0001) 上的生长
DOI：
10.1103/physrevmaterials.1.043401
复制
发表时间：
2017
影响因子：
3.4
通讯作者：
Sun L. D.
中科院分区：
文献类型：
--
作者：
Zhang Lei;Fu X.;Hohage M.;Zeppenfeld P.;Sun L. D.
The growth of pentacene thin films on a sapphire(0001) surface was investigatedin situusing differential reflectance spectroscopy (DRS). Two different film structures are observed depending on the substrate temperature. If pentacene is deposited at room temperature, a wetting layer consisting of flat-lying molecules is formed after which upright-standing molecular layers with a herringbone structure start to grow. At low substrate temperature of 100 K, the long molecular axis of the pentacene molecules remains parallel to the surface plane throughout the entire growth regime up to rather large thicknesses. Heating thin films deposited at 100 K to room temperature causes the pentacene molecules beyond the wetting layer to stand up and assemble into a herringbone structure. Another interesting observation is the dewetting of the first flat-lying monolayer upon exposure to air, leading to the condensation of islands consisting of upright-standing molecules. Our results emphasize the interplay between growth kinetics and thermodynamics and its influence on the molecular orientation in organic thin films.
