Reduced degradation in InxGa1−xAs electroluminescent diodes

Lifetests at 1000 A/cm2 have been carried out on InxGa1−xAs (0<x<0.25) electroluminescent diodes prepared by vapor-phase and liquid-phase epitaxy. As the InAs content of the alloys is increased from 0 to 25 mole%, the junction emission energy shifts from 1.4 to 1.05 eV and the degradation rate decreases by about three orders of magnitude. Consequently, diodes emitting near 1.06 μm at room temperature show little or no degradation after 1000 h at 1000 A/cm2 bias. In addition, lifetest results for a few vapor-grown GaAs1−xPx and InxGa1−xP electroluminescent diodes are consistent with the strong exponential dependence of degradation rate on emission energy observed for the InxGa1−xAs diodes. This effect has been found to be independent of large differences in growth technique, dislocation density, and initial electroluminescence efficiency. Moreover, p-n junctions of InxGa1−xAs have been found to be relatively insensitive to fabrication and device-mounting procedures that are known to be deleterious to similarly prepared diodes of GaAs. Finally, a study of the I-V characteristics and minority-carrier lifetime shows that the observed degradation is a bulk phenomenon.