Controllable surface free energy on gate dielectric for pentacene-based thin film transistors

• Main Authors: Jeng-liang Ke, 柯政良
• Other Authors: Wei-yang Chou
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/57312455169983480552

碩士 === 國立成功大學 === 光電科學與工程研究所 === 96 === We demonstrated organic thin-film transistors (OTFTs) using pentacene as the active layer. Since the shape of the pentacene molecule is rodlike shape, the induced orientation of the pentacene molecule is expected on an alignment layer which is similar to the alignment of liquid crystal molecule. The gate-dielectric of photo-aligned polyimide irradiated by a linearly polarized UV light induces the structural order of the pentacene molecules. The pentacene thin film deposited on the photo-aligned polymeric insulator is found to show the optical and the current anisotropy. By the UV light treatment, the OTFTs with the photo-aligned insulator exhibit good electrical properties in which field-effect mobility is up to 4.08 cm2/Vs. According the analyses of X-ray spectroscopy by paracrystal theory, the crystalline domain size and the degree of structural disorder of pentacene films strongly depend on the dose of UV light. Furthermore, we also observe the relationship between the coupling energy of pentacene molecules and the field-effect mobility by the polarized micro-Raman spectroscopy at various doses of UV light.