INTERFACE CHARACTERISTICS OF GAINP GAAS DOUBLE HETEROSTRUCTURES GROWNBY METALORGANIC VAPOR-PHASE EPITAXY/

The formation of parasitic GaxIn1-xAsyP1-y, intermediate layers when g rowing GaAs on GaInP or vice versa by MOVPE is investigated by the use of asymmetric GaInP/GaAs/AlGaAs double heterostructures. We found tha t such intermediate layers are only formed when growing GaAs on GaInP (inverted interface), but not for the reverse case (normal interface), resulting in a strong photoluminescence peak below the GaAs band gap. Time-resolved photoluminescence also indicates a much shorter minorit y carrier lifetime of the structures containing the inverted GaInP/GaA s interface (similar to 10 ns) compared to samples containing the norm al interface (similar to 0.5 mu s). By investigation of the interface of GaInP/AlGaAs and AlGaInP/GaAs, it is found that In carry-over is ma inly responsible for the formation of this layer in our system. By gro wing thin AlGaAs intermediate layers (1 to 2 nm) at the inverted inter face, this low-energy photoluminescence peak could be effectively supp ressed. The same could be obtained without any special means in a smal ler epitaxial system, probably due to the reduced hot susceptor surfac e.