The influence of GaN/AlN quantum dots upon the crystalline quality of AlN grown onto multi-stacked quantum dot layers was studied as a function of GaN deposition. Dislocations in AlN grown onto the quantum dot layers were bent due to the presence of the quantum dot layers and the dislocation density in the AlN was an order of magnitude lower than that in AlN grown onto sapphire substrates. In the Raman spectra, the AlN E2 frequency and GaN A1 frequency depended upon the deposition of GaN. The dependences of the frequencies were strongly correlated; suggesting that the crystalline quality of AlN was affected by the growth condition of the GaN quantum dots and that the size distribution of the dots was of great importance in reducing the dislocation density in AlN using quantum dot layers as a buffer. Reduction of dislocations was efficient when small quantum dots were grown uniformly, but inefficient when large quantum dots were grown.

Dislocation Density in AlN Grown on Multistacked GaN/AlN Quantum Dot Layers by Molecular Beam Epitaxy. N.Managaki, N.Iizuka: Physica Status Solidi C, 2009, 6[S2], S531-4