Site-selective formation of Si nanocrystal in Si O2 by femtosecond laser irradiation and Al deoxidization effects

Abstract

We have developed a robust method for fabricating Si nanoregions in silica glass using femtosecond laser processing. We attained a vivid formation of silicon-rich nanoregions site-selectively generated in Si O2 by irradiation of femtosecond laser pulses to the interface of a Si O2 substrate and deposited aluminum (Al) thin film, where the Al element acts as a gettering site for O atoms. Growth of high-density Si nanocrystals and amorphous Si was observed by transmission electron microscopy in the region that was multiply irradiated with the femtosecond laser. Furthermore, local annealing with a cw laser enhances the Si nanocrystal growth, which was determined by micro-Raman measurements. © 2008 American Institute of Physics.