Electroluminescence efficiencies of erbium in silicon-based hosts

摘要

We report on room-temperature 1.5μn electroluminescence from trivalent erbium (Er~(3+)) ions embedded in three different CMOS-compatible silicon-based hosts: SiO_2, Si_3N_4, and SiN_x. 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 Er~(3+) ions from 2% in SiO_2 to 0.001% and 0.0004% in SiN_x and Si_3N_4, respectively. Furthermore, we present strong evidence that hot carrier injection is significantly more efficient than defect-assisted conduction for the electrical excitation of Er~(3+) ions. These results suggest strategies to optimize the engineering of on-chip electrically excited silicon-based nanophotonic light sources.