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 epi taxial 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 obs ervations on InXAl1-XAs and InyGa1-yAs alloy thin films, grown by MBE on (100) and (111) InP substrates, to reveal the correlation between s ubstrate surface topography (i.e., vicinal orientations), epilayer sur face morphology, and the evolution of compositional modulations. The s pontaneous growth of vertical superlattice-like structures and quantum wire-like structures is shown. A good control for (100) InAlAs compos itional modulations has been achieved and a process enabling the direc t growth of InGaAs quantum-wire structures is described.