Formation and device application of Er-doped nanocrystalline Si using laser ablation

Laser ablation is a successful process to fabricate Er-doped nanocrystalline Si (nc-Si) thin films with high doping densities. The formed samples show intense 1.54 μm emission at room temperature. The high doping density of Er and the widening effect of the bandgap of the host nc-Si caused by fabricating Si in the nanometer scale give rise to a remarkable increase of the emission intensity of Er at room temperature. The time-response measurements under direct and indirect excitations reveal that the Er3+ ions doped in nc-Si are dominantly excited by an energy transfer process from the photo-generated electron–hole pairs. This gives hope to realizing the Si-based optical devices by current injection.