STABLE OPERATION OF ALGAAS/GAAS LIGHT-EMITTING-DIODES FABRICATED ON SI SUBSTRATE

An AlGaAs/GaAs LED (light-emitting diode) with very small degradation is fabricated in an UCGAS (undercut GaAs on Si) structure for the first time. The 43 K photoluminescence data show that the stress in UCGAS annealed at 400-degrees-C is reduced to less than 1 x 10(8) dyn/cm2. The output power from the UCGAS LED under a constant current of 800 A/cm2 degrades to 94% of the original value in the first several hours and subsequently maintains constant output for more than 1000 hours. On the other hand, the output power emitted from the conventional mesa-type LED which contains residual stress of more than 10(9) dyn/cm2 degrades quickly.