Fabrication of conical shape-Si particle by pulsed laser ablation

We have studied the effects of the laser energy density and vacuum pressure in fabricating Si particles using the PLA (pulsed laser ablation) method. Si particles were formed with different shapes depending on the laser energy density and vacuum pressure. We fabricated a conical shape-Si particle at a He gas pressure of 200 mTorr with a laser energy density of 5∼7  J/cm2. We also fabricated the hexagonal shape-Si particles and the ring shape-Si particles at the same pressure with a lower energy density and a higher energy density than that of conical shape-Si particles. Furthermore, we have known that the conical shape-Si particles had step structure with a height of 1.5 μm from FE-SEM and AFM investigations and had a single crystalline from an analysis of the Raman scattering spectroscopy. The laser energy density and the He gas pressure of the chamber affected the shape and the size of the Si particles.