Effect of the breakdown nature on Er-related electroluminescence intensity and excitation efficiency in Si:Er light emitting diodes grown with sublimation MBE technique

The influence of the p–n junction breakdown mechanism on the Er3+ electroluminescence (EL) intensity and excitation efficiency (an intra 4f transition 4I13/2→4I15/2 of Er3+ ion at the wavelength of 1.54 μm) has been investigated in Si:Er light emitting diodes (LED) grown with sublimation molecular beam epitaxy (SMBE) method. It is shown that the avalanche LEDs are characterized by a greater Er3+ EL intensity and excitation efficiency compared with the tunnel LEDs. At the same time, an excessive advance into the avalanche breakdown parameter region leads to microplasma breakdown of the p–n junction, which causes a non-uniform distribution of the drive current density over p–n junction area and an appreciable decrease of the Er3+ EL intensity. Si:Er LEDs operating in mixed breakdown conditions seem to be more preferable for reaching maximal Er3+ EL intensity at room temperature, as they provide an optimum combination of high Er3+ EL excitation efficiency with the uniformity of the p–n junction breakdown.