Potential use of the tendency of III-V alloys to separate for fabrication of low dimensionality structures

Improved understanding and control of compositional modulations in epitaxial III-V alloys can result to efficient fabrication methods for 1-D and 0-D quantum device structures. We have made TEM, SEM aad AFM observations on InXAl1-XAs and InyGa1-yAs alloy thin films, grown by MBE on (100) and (111) InP substrates, to reveal the correlation between substrate surface topography (i.e., vicinal orientations), epilayer surface morphology, and the evolution of compositional modulations. The spontaneous growth of vertical superlattice-like structures and quantum wire-like structures is shown. A good control for (100) InAlAs compositional modulations has been achieved and a process enabling the direct growth of InGaAs quantum-wire structures is described.