Films grown onto buffer layers containing quantum dots, by molecular beam epitaxy onto sapphire substrates, were investigated. The density of the dislocations in the films was determined by wet chemical etching and atomic force microscopy. It was found that the insertion of a set of multiple GaN quantum-dot layers into the buffer layer effectively reduced the density of the dislocations in the epitaxial layers. When compared to the dislocation density of about 1010/cm2 in typical GaN films grown onto an AlN buffer layer, a density of about 3 x 107/cm2 was found in GaN films grown with quantum dot layers.

Defect Reduction with Quantum Dots in GaN Grown on Sapphire Substrates by Molecular Beam Epitaxy. D.Huang, M.A.Reshchikov, F.Yun, T.King, A.A.Baski, H.Morkoç: Applied Physics Letters, 2002, 80[2], 216-8