第192回応用セラミックス研究所 講演会(Ms.Giordano, Milano-Bicocca Univ.)
| 開催日時 | 2011年06月21日 15：00－ |
|---|---|
| 開催場所 | Ｊ１棟３１３号室 |
| 主催 | 応用セラミックス研究所 |
| 連絡先 | 須崎 友文 (内線5360） |
プログラム等
講師： Livia Giordano
Universita degli Studi Milano-Bicocca 大学 研究員
テーマ： Oxide ultrathin films on metal supports
<<概要>>
In our everyday life, we all make use of oxide ultrathin films, since they are essential for the functionality and reliability of objects of common use, such as mobile phones and laptops. In fact, ultrathin silicon dioxide films represent an unsurpassed material in the design of metal oxide field effect transistors, and the excellent properties of thin SiO2 films grown on silicon have certainly favoured the microelectronic revolution as we know it. However oxides at the nanoscale (typically up to 10 nm in thickness) are also used in many other systems and devices. In some cases they form under normal reactive conditions and are essential to confer specific properties to a material (e.g. corrosion protection of metals by passive films). Other systems and devices are especially designed to exploit the reduced oxide thickness, such as ferroelectric ultrathin film capacitors, tunneling magnetoresistance sensors, or solar energy materials.
Oxide ultrathin films grown on metals may present unusual properties related to the reduced thickness and to the presence of the substrate, which allow to grow phases unknown in bulk materials. Moreover, electron transport through the film may induce spontaneous charging of species adsorbed on the film. [1] The charging has implications namely on the shape of deposited metal clusters and on the reactivity of the adsorbates. [2] These phenomena have been proposed theoretically by means of density functional theory calculations and then proved experimentally, showing the prediction possibility of theoretical modeling. Moreover, the metallic substrate in principle can help in stabilizing polar oxide orientations. The different polarity-related mechanisms and contributions at work on supported ultra-thin films are analyzed by DFT calculations for the case of MgO(111). [3]
