Fritz Sandra E, Martin Stephen M, Frisbie C Daniel, Ward Michael D, Toney Michael F
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA.
J Am Chem Soc. 2004 Apr 7;126(13):4084-5. doi: 10.1021/ja049726b.
Grazing incidence X-ray diffraction reveals that a pentacene monolayer, grown on an amorphous SiO2 substrate that is commonly used as a dielectric layer in organic thin film transistors (OTFTs), is crystalline. A preliminary energy-minimized model of the monolayer, based on the GIXD data, reveals that the pentacene molecules adopt a herringbone arrangement with their long axes tilted slightly from the substrate normal. Although this arrangement resembles the general packing features of the (001) layer in single crystals of bulk pentacene, the monolayer lattice parameters and crystal structure differ from those of the bulk. Because carrier transport in pentacene OTFTs is presumed to occur in the semiconductor layers near the dielectric interface, the discovery of a crystalline monolayer structure on amorphous SiO2 has important implications for transport in OTFTs.
掠入射X射线衍射表明，在通常用作有机薄膜晶体管（OTFT）介电层的非晶SiO₂衬底上生长的并五苯单层是晶体。基于掠入射X射线衍射数据的单层初步能量最小化模型表明，并五苯分子呈人字形排列，其长轴相对于衬底法线略有倾斜。尽管这种排列类似于块状并五苯单晶中（001）层的一般堆积特征，但单层晶格参数和晶体结构与块状的不同。由于并五苯OTFT中的载流子传输被认为发生在介电界面附近的半导体层中，因此在非晶SiO₂上发现晶体单层结构对OTFT中的传输具有重要意义。
