Reduction of the dislocation density in GaN during low-pressure solution growth

Three-dimensional facetted islands form initially during low-pressure solution growth of GaN even without the presence of masking layers. Observations by transmission electron microscopy show that threading dislocations bend towards the facets of these islands. In consequence, a significant reduction of the dislocation density takes places within the first micrometer of the growing layer. Calculations of the line energy of the dislocations near the island facets with consideration of the Burgers vector and the inclination of the growth facet against the (0 0 0 1) plane can predict the bending angles of the dislocations. Therefore, measures reducing the dislocation density with thickness of the growing layers can be developed.