COMPARISON OF ALGAINP LIGHT-EMITTING-DIODES ON N-GAAS AND P-GAAS MISORIENTED SUBSTRATES PREPARED BY LOW-PRESSURE METALLORGANIC VAPOR-PHASE EPITAXY

The growth and characterization of AlGaInP double-heterostructure oran ge light-emitting diodes (LEDs) grown on n- and p-GaAs misoriented sub strates by low-pressure metallorganic vapor-phase epitaxy are presente d. Zinc and silicon are used as p- and n-type dopants for AlGaInP, res pectively. The device performance is found to be strongly dependent on the doping concentration in both upper and lower cladding layers for the p-substrate LEDs. However, for the n-substrate LEDs, the strong de pendence is only found on the doping concentration in the upper claddi ng layer. The degradation of device performance with increasing doping concentration in the cladding layer is thought to be due to the light absorption by deep levels. After optimizing the doping concentration in the LEDs, better LED performance can be obtained by using the p-typ e substrate. This demonstrates the feasibility of fabricating AlGaInP LEDs grown on p-GaAs substrates.