The microstructure of Inx Al1-x NGaN heterostructures (where x∼0.13-0.19), grown by molecular beam epitaxy, was investigated by transmission electron microscopy. Observations in the cross-section and plan-view geometries show evidence for lateral phase separation originating at the GaN surface that results in a vertical honeycomblike structure within the InAlN layers. The lateral dimensions of the honeycomb cells are ∼5-10 nm. The vertical walls are In rich with a width of ∼1-2 nm and align roughly perpendicular to 〈11 2- 0〉 and 〈1 1- 00〉 directions. The phase separation is attributed to random compositional fluctuations during the early stages of growth, possibly associated with misfit-strain relaxation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)