Observation of dodecagon-shape V-defects in GaN/AIInN multiple quantum wells

摘要

The microstructure of GaN(Si)/AlInN multiple quantum wells grown on GaN/Al_2O_3 (0001) templates by metalorganic vapor-phase epitaxy has been investigated using transmission electron microscopy and associated techniques. Dodecagon-shape V-defects with hexagonal apexes, which nucleate on screw-component threading dislocations, are observed at the film surface. The hexagonal apexes are bounded by {1121} planes, whereas the dodecagons are bounded by {1011} and {1121} planes, where the {1011} facets are generated from the edges between adjacent {1121} planes. Indium segregation is observed along these edges. A possible reason for formation of these defects is briefly discussed.