Inp-alinas “strain free” early stages heteroepitaxy leading to nanostructure formation by MOVPE

We show that heteroepitaxy of thin films of InP on Al_0.48In_0.52As by MOVPE does not result in continuous flat layer growth, but instead develops a number of low dimensional structures, e.g. quantum dots and rings. We consider local phase separation/alloying-induced strain and preferred aggregation of adatom species on the substrate surface together with reduced wettability of InP on AlInAs to be the cause of the observed surface organization. This behavior has not been previously reported, and it opens a new application window for creating strain-free type-II staggered QD structures for possible applications in optical memories, detectors, and solar cells.