A STUDY OF GAINP GAAS INTERFACES - METALLURGICAL COUPLING OF SUCCESSIVE QUANTUM-WELLS/

We present a study of GaInP/GaAs interfaces by means of photoluminesce nce (PL) of multi quantum wells (MQW), embedded in GaInP, or asymmetri c structures having an AlGaAs barrier GaInP/GaAs/AlGaAs. The PL energi es of quantum wells were compared with calculations based on the trans fer matrix envelope function approximation, well suited for asymmetric structures. GaInP/GaAs/AlGaAs MQW structures (GaInP grown first) are in reasonably good agreement with calculations. Reverse ones, AlGaAs/G aAs/GaInP, present a lower PL energy than calculated. But the agreemen t with theory is recovered on single quantum well samples, or in MQW w hen the GaInP thickness is increased up to 100 nm. We interpret this p henomenon as a diffusion of arsenic atoms from the next GaAs well thro ugh the GaInP barrier. Arsenic atoms exchange with phosphorus atoms at the GaInP-on-GaAs interface of the former well, leading to a small ga p strained InGaAs region responsible for the lowering of PL energies. (C) 1998 Academic Press Limited.