Injection‐type light‐emitting devices using rare‐earth‐doped III‐V semiconductors

Abstract

We have fabricated Er,O‐codoped GaAs (GaAs:Er,O) 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 LEDs 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. EL intensity increased linearly with current density. Subsequently, the intensity exhibited a tendency to saturate at higher current densities. The current density dependence of EL intensity revealed an extremely large excitation cross section (approximately 10−15 cm2) of Er ions by current injection. This large Er excitation cross section was confirmed by time‐resolved measurements of EL intensity. It is two orders of magnitude larger than that of Er‐doped Si LEDs (6×10−17 cm2). GaInP/GaAs:Er,O/GaInP double‐heterostructure (DH) LEDs have also been fabricated. The saturated EL intensity significantly increased with increasing GaAs:Er,O active‐layer thickness.