Periodic Nanodots and Nanolines on Indium-Tin-Oxide Films Induced by Femtosecond Laser Pulses

• Main Authors: Wang, Chih, 王智
• Other Authors: Leu, Jih-Perng
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/73985570886745563660

博士 === 國立交通大學 === 材料科學與工程學系 === 100 === In this study, large-area surface ripple structures of indium-tin-oxide films, composed of self-organized nanodots, were induced by femtosecond laser pulses, without scanning and an objective lens. The multi-periodic spacing (~800 nm, ~400 nm and ~200 nm) was observed in the laser-induced ripple of ITO films. The local conductivity of ITO films is significantly higher, by approximately 30 times, than that of the as-deposited ITO films, due to the formation of these nanodots. Such a significant change can be ascribed to the formation of indium metal-like clusters, which appear as budges of ~5 nm height, due to an effective volume increase after breaking the In-O to form In-In bonding. Furthermore, two types of periodic nanostructures, self-organized nanodots and nanoline can be easily and reliably obtained by precisely controlling the fluences and numbers of femsecond laser pulses. The multiple periodicities (~800 nm and ~400 nm) were clearly observed on the ITO films with nanodot and nanoline structures and identified by 2D-Fourier transformation patterns. Both of them show the anisotropic characteristics in visible range, which is strongly correlated with the geometry and the metallic content in the laser-induced nanostructures.