On the environment of optically active Er in Si-electroluminescence devices

We report sharp, atomlike electroluminescence spectra close to 1.54 μm from a low-dose (3.5×1018 cm−3) erbium-implanted silicon light-emitting diode operating under forward bias. The well-resolved Stark splitting identifies the isolated interstitial Er with cubic site symmetry as the source. The full width at half maximum of the most intense line is 0.5 nm. A comparison with a highly Er (5×1019 cm−3) and O (1×1020 cm−3) doped diode with a high doping gradient grown by molecular beam epitaxy and with Er-implanted silica is given with respect to fine structure and thermal quenching. The room-temperature emission of the highly Er and O doped diode is ascribed to Er containing silica precipitates within the c-Si matrix.