Room temperature 1.5 μm electroluminescnence from GaInP/Er,O-codoped GaAs/GaInP double heterostructure injection-type light emitting diodes grown by organometallic vapor phase epitaxy

We have fabricated GaInP/Er,O-codoped GaAs (GaAs:Er,O)/GaInP double heterostructure (DH) injection-type light emitting diodes (LEDs) by organometallic vapor phase epitaxy (OMVPE) and investigated their electroluminescence (EL) properties under forward bias at room temperature. The EL spectrum from a cleaved edge of the LED was dominated by the luminescence due to an Er-2O center, indicating that injected carriers contribute effectively to the excitation of the Er-2O center. The EL intensity increased linearly with the current density. Subsequently, the intensity exhibited a tendency to saturate at higher current densities. The current density dependence of the EL intensity revealed an extremely large excitation cross-section of Er ions by current injection, approximately 10-15 cm2. It is by two orders in magnitude larger than that of Er-doped Si LEDs (6x10-17 cm2), while it is by five orders of magnitude larger than the optical excitation cross-section in Er-doped fiber amplifiers (10-20 to 10-21 cm2). The saturated EL intensity was largely enhanced with increasing GaAs:Er,O active layer thickness