Erbium-doped silicon nanocrystals in silicon/silicon nitride superlattice structures: Light emission and energy transfer

In this paper, we discuss optical emission, energy transfer and electroluminescence from a superlattice structure containing small (∼2 nm diameter) amorphous silicon (Si) clusters coupled to erbium (Er) ions. The superlattice structure is fabricated by direct co-sputtering of thin (∼3-5 nm) Er-doped silicon-rich nitride/Si (Er:SRN/Si) layers subsequently annealed at different temperatures in order to induce the nucleation of Si clusters and to activate Er emission. In this paper, we discuss efficient Er emission and sensitization with nanosecond-fast non-radiative transfer time and we report on low turn-on voltage (∼7 V) electroluminescence from simple electrical device structures. Our results demonstrate that small Si clusters embedded in silicon nitride-based superlattice structures provide a viable approach for the fabrication of Si-compatible optical devices.