Long- and short-period nanostructure formation on semiconductor surfaces at different ambient conditions

We present the results of studies of nanoripples formation during interaction of the 800 nm, 120, and 35 fs pulses with semiconductor surfaces. Simultaneous appearance of the ripples with the period (700 nm) close to the wavelength of interacting radiation and considerably smaller period (180 nm) was achieved. We discuss the experimental conditions for the formation of these nanoripples (incidence angle, polarization, number of shots, etc.). We show a decisive role of surrounding medium on the quality of nanoripples formation. The self-organization of high-quality nanoripples was clearly shown in the case of dense surrounding medium ( methanol), while in the case of insufficient amount of surrounding material (i.e., at different vacuum conditions), the quality of ripples considerably decreased. (C) 2010 Optical Society of America