日 時：2009年8月２１日（金）11:00～12:00
場 所：南７号館 １階 １０１会議室(学科会議室)
講 師：Prof. Woong Lee(Schoolof Nano & Advanced Materials Engineering,Changwon National University, Changwon, Republic of Korea)
講演題目：「Low-dimensional Systems & Their Applications」
講演内容：
In this seminar, experimental study of ZnO-based systems and the ab initio studies on carbon-aluminium systems are introduced with some major findings and achievements.
1. Preparation of ZnO-based Low-dimensional Structures and Their Device Applications
Various low-dimensional structures have been studied for their fabrications and device applications. As a two-dimensional nanostructure, Al-doped zinc oxide (ZnO:Al) films were applied to liquid crystal displays (LCDs) as transparent electrodes substituting indium tin oxide (ITO). While the ZnO:Al-based twisted nematic LCD cell showed similar operational behaviour to ITO-based counterpart, its electro-optical and residual DC characteristics were somewhat improved, which is attributed to the substantially lower density of charge carrier trapping centres in the polyimide layer/electrode interface region, demonstrating high application potential of ZnO:Al films as transparent electrodes of LCDs.
2. First Principle Study of Carbon-Aluminium Interfaces for CNT-dispersed Composites
A series of ab initio simulations were carried out for nanocomposite systems constituted of a graphene sheet and an Al (111) layer with various registries to investigate their dispersion relations, i.e. the bonding energy as a function of inter-layer distance, in combination with the electronic structures. It was predicted that the graphene/Al interface at the fundamental nano-unit level has substantially different characteristics from bulk graphite-Al systems in that its type of bonding is partially localized metallic with a cohesive energy substantially larger than that of typical bulk system graphite/Al interface. With the introduction of in-plane compressive strains in the Al (111) layer, the equilibrium interfacial bond length increased, accompanied by noticeable decrease in the cohesive energy, while the interface bonding became a weak secondary type. In summary, the predicted registry dependence of the electronic structures (or the nature of bonding) of the C-Al interface, varying between weak covalent to weak metallic, would provide some guideline for the proper choice of the material processing in the preparation of the nanocomposites with suitable interfacial strengths.
問合せ先：篠崎和夫，内線: 2518 (J.S. Cross ext. 3723, J. Cho ext. 3367)