カーボンナノチューブ垂直配向膜を透過する気体分子の散乱挙動

摘要

Scattering process of gas molecules on vertically aligned single-walled carbon nanotube (VA-SWNT) films was investigated using molecular beam technique. The surface modification with VA-SWNT films was found to significantly enhance energy accommodation of helium molecules, which tends to be inefficient even on contaminated or rough surfaces because of the large mass mismatch between helium and surface atoms. Our results indicate that the surface modification with VA-SWNT films is promising for enhancing heat transfer across surfaces in microanoscale devices. The efficient energy transfer originates from high porosity of the films, which enables gas molecules to penetrate into the film and have multiple collisions with SWNTs. In order to reveal the scattering process within the film, we also conducted the measurements with freestanding VA-SWNT films. Even for the film as thin as 0.1 μm, most of the molecules are well accommodated and are reflected or transmitted diffusively through the film while few molecules are transmitted without any interaction.%近年，マイクロ?ナノデバイスの研究開発の進展にrn伴い，電力密度の増加に対応するための効果的な除熱rn技術が求められている．系のスケールが小さくなるrnと，熱輸送が界面熱抵抗に支配されるようになるため，rn界面現象の理解と制御が不可欠である．