The effect of laser wavelength on the formation of surface-microstructured silicon

Abstract

We experimentally investigated the properties of the surface-microstructured silicon fabricated by 800 and 400nm laser pulses. We found that as the increasing of pulse number, the average height of spikes fabricated by the 800nm laser pulses increases more than that of the 400nm laser pulses. This is due to that the formation of the conic spike structure is originated from the conical distribution of incident laser energy in the sample, and the height of cone is proportional to the penetration depth of the laser pulse. Additionally, by comparing the samples which have similar average height of spikes, we found that the denser interval of spikes fabricated by the 400nm wavelength laser pulses has higher absorption coefficient than that of 800nm laser pulses. These results are beneficial for the preparation of high absorption surface-microstructured silicon.