Electroluminescence efficiencies of erbium in silicon-based hosts

We report on room-temperature 1.5 μm electroluminescence from trivalent erbium (Er3+) ions embedded in three different CMOS-compatible silicon-based hosts: SiO2, Si3N4, and SiNx. We show that although the insertion of either nitrogen or excess silicon helps enhance electrical conduction and reduce the onset voltage for electroluminescence, it drastically decreases the external quantum efficiency of Er3+ ions from 2% in SiO2 to 0.001% and 0.0004% in SiNx and Si3N4, respectively. Furthermore, we present strong evidence that hot carrier injection is significantly more efficient than defect-assisted conduction for the electrical excitation of Er3+ ions. These results suggest strategies to optimize the engineering of on-chip electrically excited silicon-based nanophotonic light sources