1.3 μm emitting GaInNAs/GaAs quantum well resonant cavity LEDs

The electrical and optical characteristics of a set of MBE-grown 1.3 μm emitting GaInNAs/GaAs quantum well (QW) resonant cavity light-emitting diodes (RCLEDs) have been analyzed as a function of the growth temperature of the distributed Bragg reflector (DBR) and the contact alloying. The RCLEDs consist of a λ-long microcavity delimited on one side by an 8-pair AlAs/GaAs DBR and on the opposite side by a metallic mirror, with the QW located at one of the antinodes of the standing wave. The structures are designed for extraction of the light through the substrate. Room-temperature electroluminescence at 1.3 μm is demonstrated with 38% In and 1.3% N in the quantum well. It is found that the RCLEDs with the DBR grown at the lowest temperature of 670 °C show a lower differential slope efficiency and degraded current-voltage characteristics, i.e. higher ideality factor, lower shunt resistance and lower threshold voltage. This degradation can be explained to arise from the higher roughness observed in the DBRs grown at 670 °C, which likely enhance the formation of point defects and compositional inhomogeneities in the quantum well. Alloying of the ohmic contacts also results in a widening of the electroluminescence emission, probably due to the degradation of the top metallic mirror sharpness caused by the diffusion of the metal into the GaAs. The best results in terms of differential slope efficiency and electrical characteristics are obtained when the DBRs are grown at 750 °C and the contacts are left non-alloyed.