Nanograting fabrication on the surface of silicon and gallium arsenide using femtosecond laser pulses

Self-organized nanogratings were formed with a period of sub-wavelength on the surfaces of Si and GaAs wafers by scanning a femtosecond laser beam at 800nm with appropriate irradiation conditions. The periodicity and shape of the nanogratings formed on the surfaces of two semiconductors were studied with different laser polarizations and various scan speeds. We also studied the profile and variation of the nanograting depth from the surface by atomic force microscope (AFM) analysis, and merged neighboring nanogratings to form a large area of grating structure.