METALORGANIC VAPOR-PHASE EPITAXY-GROWN QUANTUM-WELL STRUCTURES WITHIN BARRIERS OF INP AND GAINP - A COMPARISON

In the present work, the quality of hetero-interfaces produced by metalorganic vapor phase epitaxy (MOVPE) in the InP-based GaInAs/InP system and the GaAs-based GaAs/GaInP system will be compared. We use the photoluminescence of few monolayer thick quantum wells (QWs) as a probe. The half-widths of the photoluminescence peaks of GaInAs/InP QWs indicate that these structures can be optimized to grow with laterally very nat interfaces, where the spacing between islands of different thickness is much larger than the excitonic diameter of about 100 Angstrom. Low growth rates (less than or equal to 1 ML/s) and moderate temperatures (approximate to 600 degrees C) are the necessary growth parameters. The comparatively poor results for thin GaAs/GaInP QWs, where the half-widths of the QW PL peaks approximately follow the calculated values for an interface roughening in the 1 ML scale, characterize the present state-of-the-art of growing this material combination. In contrast, 1 and 2 ML thick InP QWs in GaInP barrier material, showing sharp PL peaks of about 11 meV width, can be produced under similar deposition conditions. This indicates that also GaInP/InP QW interfaces can be grown rather flat and confirms that it is the As-P exchange reaction which deteriorates the interface flatness in the GaAs/GaInP system. In which way the GaInP interfaces are more sensitive toward P/As exchange reactions than InP interfaces remains unclear.