GROWTH OF PSEUDOMORPHIC INXGA1-XAS GAPYAS1-Y MULTIPLE-QUANTUM-WELL STRUCTURES ON GAAS BY GAS-SOURCE MOLECULAR-BEAM EPITAXY/

We report gas source molecular beam epitaxial growth of strain balance d InxGa1-xAs/GaPyAs1-y multiple quantum well structures on GaAs that e xhibit sharp excitonic absorption features at 1.06 Am. Because these m aterials also lie at the extreme limit of elastic stability, we examin e the mechanism by which strain initially relaxes using RHEED and X-ra y diffraction. A structural instability is found for a critical strain layer thickness beyond which a transition from smooth to rough growth occurs. When strain relaxation occurs our measurements indicate that surface energy driven processes cause the layer to form lateral domain s. The domains consist of regions containing small misorientation angu lar tilts. Domain formation has a direct consequence on the field depe ndent absorption measurements in strain balanced multiple quantum well structures on GaAs.