Arbitrary surface structuring of amorphous silicon films based on femtosecond-laser-induced crystallization

The arbitrary surface structuring of amorphous silicon (a-Si) films was performed by applying the Fourier-transform (FT) method to the femtosecond-laser-induced crystallization. In order to realize the arbitrary structuring, the logo q-Psi was produced in the a-Si film by the FT of a computer-generated hologram. The crystallization of a-Si was performed using the near-infrared femtosecond-laser pulses. By micro-Raman spectroscopy, scanning-electron microscopy, and transmission-electron microscopy, it was found that the femtosecond-laser pulses induced a localized phase transformation from the amorphous to the crystalline phase, and the spatially selected crystallization of the a-Si was responsible for the formation of the two-dimensional pattern. (c) 2006 American Institute of Physics.