Periodic silicon surface structures fabricated by infrared nanosecond pulse laser ablation in ambient air for enhanced anti-reflection

Abstract

At present, there are many problems such as high cost and high pollution in fabrication methods of anti-reflective structures on silicon surfaces. To solve this problem, the utilization of nanosecond pulse infrared laser processing technology is proposed to realize the fabrication of anti-reflective structures on silicon surfaces. Compared with polished silicon, the reflectance of the silicon surface with the anti-reflective structure can be reduced by 89% in the visible light band. In order to unfold the anti-reflection mechanism of the black silicon substrate and optimize the structures, finite difference time domain (FDTD) is adopted to simulate the anti-reflective conical structure with tunable aspect ratios and generate the corresponding reflectance spectrums. To optimize the aspect ratio of silicon surface structure, the processing parameters of nanosecond pulse infrared laser are investigated, which not only realizes the morphology control of the surface structure but also optimizes the anti-reflective performance of the silicon surface. The result shows that the reflectance of the silicon surface is reduced to 3.87% in the visible light band by the anti-reflective structure fabricated by nanosecond pulse infrared laser processing. Also, the variation of aspect ratio of the structure could be monitored and predicted by acoustic signal detection technique. This detection technique provides potential applications in structural integrity monitoring during the fabrication process.