Current injection 154 µm light-emitting devices based on Er-doped GaN/AlGaN multiple quantum wells

Abstract

We report on the growth, fabrication and electroluminescence (EL) characteristics of light-emitting diodes (LEDs) based on Er-doped GaN (GaN:Er) and GaN/AlGaN multiple quantum well (MQW:Er) active layers. The LED structures were grown using metal organic chemical vapor deposition and processed into 300x300 µm 2 mesa devices. The LEDs exhibit emission at 1.54 µm, due to Er intra-4f transitions, under forward bias conditions. The 1.54 µm emission properties from LEDs with MQWs:Er and GaN:Er active layers were probed. The LEDs fabricated using MQWs:Er exhibited improved performance as evidenced by a factor of 4 enhancement in the optical power output as compared to conventional GaN:Er based LEDs. The results demonstrate a significant advance in the development of current injected, chip-scale emitters and waveguide amplifiers based on Er doped semiconductors.

Physics of Efficiency Droop in GaN:Eu Light-Emitting Diodes

“… 21 , where they showed an increase of the PL intensity of a AlGaN/GaN:Eu/AlGaN multiple QW structure as compared to a rudimentary GaN:Eu based light emitter. Similar findings have been demonstrated for Erbium-doped GaN based heterostructures, where the effect of carrier confinement increases the luminescence of the GaN:Er emitter 37 , 38 .

Figure 8 Effect of carrier confinement on ( a ) current injection efficiency (η injection ) and ( b ) excited Eu +3 ion concentration of the GaN:Eu active region.

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“…Both the carrier mobility and length of the device active regions affect the transport time. Furthermore, the utilization of heterostructure will be beneficial for the internal quantum efficiency (η IQE ), attributed to the stronger carrier localization which in turn increases the trap capture probabilities 21 , 37 , 38 . In order to obtain a more efficient excitation of Eu +3 ion, co-doping and strain engineering in the GaN host are possible pathways.…”