Nanoscale flow deformation of silicate glass ultrathin films for development of nano-patterned glass surfaces

The nanoscale behavior of high-temperature flow deformation for silicate-based oxide glass ultrathin films was characterized with focus on forming a nano-patterned glass surface. The oxide glass thin films were deposited at room temperature by pulsed laser deposition onto the ultrasmooth sapphire substrates with 0.2-nm-high atomic steps. It was found from atomic force microscopy (AFM) measurements that the silicate ultrathin films (about 3 nm thick) started to deform at a temperature 50 °C lower than the glass transition point of the bulk glass. The glass thin films annealed at high temperatures exhibited the nano-stepped surface structure reflecting the sapphire substrate surface. By scanning the AFM tip on the as-deposited glass film in a contact mode and then thermal annealing the film, we could pattern the nano-stepped glass surface at a nanoscale.