Hybrid Microstructures on Si Surface Formed by Nanosecond Pulse Laser for Broadband Antireflection

In this paper, a hybrid quasi-micro-pyramid structure is fabricated via nanosecond pulse laser micro-processing, which demonstrates a 15% drop in average reflectance as compared to the uniform quasi-micro-pyramid structures. The influences of laser fluence, pulse number, and designed pitch are also studied experimentally and systematically. The results show that reflection increases with the pattern pitch, decreases with pulse number, and a minimum in reflection is reached at a laser fluence of 4.83 J/cm2. The method here demonstrated provides an alternative and low-cost solution for broadband anti-reflection by hybrid structures with normal aspect ratio rather than uniform structures with high aspect ratio. Higher antireflection performance can be expected by optimizing the laser processing parameters.