Silicon is one of the most used materials in nanostructure research and in a wide range of high-technological applications spanning from the fine chemical industry to medicine and to semiconductor electronics. The processes underlying laser-induced nanostructuring of Si surfaces are still not fully understood. In particular, it is not completely clear how individual surface defects contribute to generation of ordered structures. In this contribution, we report on the influence of random defects, which are present on silicon surfaces, on the formation of periodic surface structures by laser irradiation with femto- and picosecond pulses. A thorough analysis of the results leads to the conclusion that the surface defects act as antenna-like elements directing radiation along the sample surface and determining the location, directionality and quality of structuring.
Science Journal 