Erbium-silicon light-emitting diodes grown by molecular beam epitaxy: Optical properties

We present erbium-oxygen-doped silicon light-emitting diodes fabricated by molecular beam epitaxy containing concentrations of up to 2 × 10²⁰ cm^-3 erbium and 10²¹ cm^-3 oxygen. The diodes show electroluminescence at 1.54 μm originating from the intra-4f transition of erbium for both, forward and reverse bias conditions. In cases of low dopant concentrations, the reverse bias electroluminescence shows nearly no quenching of intensity between 5 K and room temperature and is considerably stronger than under forward bias operation. Diodes with the highest erbium and oxygen concentrations, however, show nearly identical temperature quenching of the erbium electroluminescence for both biasing conditions, the reverse bias intensity still being considerably higher.