Three-dimensional facetted islands formed initially during the low-pressure solution growth of GaN even without the presence of masking layers. Observations by transmission electron microscopy showed that threading dislocations bent towards the facets of these islands. As a consequence, a significant reduction of the dislocation density took place within the first micrometer of the growing layer. Calculations of the line energy of the dislocations near to the island facets, taking account of the Burgers vector and of the inclination of the growth facet to the (00•1) plane could predict the bending angles of the dislocations. Therefore, measures which reduced the dislocation density with the thickness of the growing layers could be developed.

Reduction of the Dislocation Density in GaN during Low-Pressure Solution Growth. I.Y.Knoke, E.Meissner, J.Friedrich, H.P.Strunk, G.Müller: Journal of Crystal Growth, 2008, 310[14], 3351-7