Atomic force microscopy of laser induced sub-micrometer periodic structures on implanted fused silica and silicon

The ultrathin layers with depth from 30 to 60 nm and optical absorption coefficient up to 105 cm−1 were created on the fused silica and crystalline silicon surfaces by Fe and Sb ions bombardment respectively. Nanometer-scale α-Fe particles formed into glass surface layer by high dose Fe+ bombardment were responsible for optical absorption in the Fe+ implanted fused silica. The increase in the optical absorption of Si after Sb+ implantation are due to transformation of the silicon surface layer from the crystalline to the amorphous state. These layers were found to be easily evaporated by pulsed beam of UV and visible lasers due to their high light absorption. Such materials may be promising in manufacturing the video disk master. The sub-micrometer diffraction gratings were produced using holographic method in order to estimate the possible resolution of these media for optical data storage. It was found with Atomic Force Microscope (AFM) that microtopography of laser-induced diffraction gratings is determined by the size of optical absorption centers. After treatment with higher laser power density the half-micrometer bi-directional diffraction gratings on implanted silicon were observed by AFM. The origin of these gratings was explained in terms of the laser-induced surface electromagnetic waves.