AlGaInP microcavity light-emitting diodes at 650 nm on Ge substrates

We demonstrate microcavity light emitting diodes (MCLEDs) emitting at 650 n m on Ge substrates, Ge has the advantage of lower cost and higher strength compared to GaAs substrates. The multi-quantum well microcavity devices con sisted of AlGaAs-based distributed Bragg reflector (DBR) mirrors, AlGaInP a ctive material with an additional 5-mu m p-Al0.55Ga0.45As current spreading layer on top of the p-DBR. A maximum external quantum efficiency of 4.35% and an optical power higher than 5 mW was obtained for a device with 200-mu m diameter. The results indicate the potential use of MCLEDs on Ge for vis ible LEDs.