Comparison of Laser Textured Silicon Surfaces Prepared by Different Laser Sources

Four different lasers with various wavelengths, pulse lengths and intensities were applied for laser ablation resulting laser textured, “black” silicon surfaces. The aim is to compare the optical properties of samples structured by the different lasers, and so to find the optimal configuration and to investigate its viability for photovoltaic applications.At this first stage, the evolution of the significantly different surface morphologies produced by the four configurations is studied by scanning electron microscopy together with the characterization of the resulted surface reflectance. The underlying physical mechanisms related to laser ablation processes are discussed explaining the shape of the resulted structures. Based on the trend of the morphology and reflectance changes, a minimal number of laser shots resulting sufficient antireflective property was determined. Around 2% total reflectance was achieved in the visible and near infrared spectral ranges texturing by some tenth of pulses from the sub-picosecond excimer laser.