MOLECULAR-BEAM EPITAXIAL-GROWTH OF GAAS, ALAS AND AL0.45GA0.55AS ON (111)A-(001) V-GROOVED SUBSTRATES

Molecular beam epitaxial (MBE) growth of GaAs, AlAs, and AlGaAs on V-grooved GaAs substrates are studied. Observing the morphology of the heterostructures grown on the various part of V-grooves with scanning electron microscopy (SEM), it is shown that GaAs, AlAs and AlGaAs have different elemental growth parameters such as surface diffusion and atom incorporation, leading to the difference in growth behavior. Under appropriate growth conditions, in particular, the growth of AlAs results in very smooth surface on the (111)A sidewalls and drastic sharpening at the bottom of the V-grooves, whereas the growth of AlGaAs and GaAs do not show such phenomena. MBE growth mechanisms, both on the V grooved substrates and on the (111)A flat surface, are discussed based on the phenomena observed in our experiments. Furthermore, we investigate the growth temperature dependence of the morphology and the surface diffusion of atoms during the growth of GaAs/AlAs heterostructures on the V-grooves, and demonstrate the successful fabrication of GaAs multiple quantum-wire structures at the bottom of the V-grooves by high-resolution SEM observations and cathodoluminescence measurements at 16 K.