Electron microscopy has been used to characterize the microstructure of InN quantum dots (QDs) grown by molecular-beam epitaxy on GaN(0001)/AlN(0001)/ sapphire substrates at 425 °C under slightly group III-rich conditions. Observations in plan-view and cross-section geometries established that the large majority of the InN QDs were invariably associated with threading dislocations in the underlying GaN buffer layer having edge components. Periodic, primarily hexagonal, arrays of misfit dislocations separated by ∼2.8 nm were observed at the InN QD/GaN interface, indicating that the QDs were almost completely relaxed. No evidence for an InN wetting layer was obtained either in situ by reflection high-energy electron diffraction or ex situ by transmission electron microscopy.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)