Erbium-doped slot waveguides containing size-controlled silicon nanocrystals

Silicon based slot waveguides with a slot containing Si nanocrystals (Si-nc) and Erbium ions (Er3+) inside a silica matrix were prepared using sputter deposition and low-energy ion implantation. This sequence enabled independent optimization of nanocrystal formation and Er3+ incorporation parameters. Using a superlattice approach, the size of the Si-nc inside the slot could be controlled and optimized for maximum Er3+ luminescence yield at 1.54 mu m. Er3+ is found to be efficiently pumped by Si-nc of sizes around 3 to 4 nm. Increasing Er3+ photoluminescence at 1.54 mu m with increasing post-implantation annealing temperatures up to 1000 degrees C is attributed to annealing of matrix or Si-nc interface defects mainly. Additionally, a dependence of the Er3+ luminescence intensity on both the excitation and emission linear polarization orientation is shown, which demonstrates efficient field enhancement in sputtered slot waveguide structures. (C) 2015 AIP Publishing LLC.