[摘要]：We report the use of microfocused three-dimensional x-ray reciprocal space mapping to study InGaN epilayers with average InN content similar to 20%-22%. Analysis of the full volume of reciprocal space, while probing samples on the microscale with a focused x-ray beam, allowed us to gain valuable information about the nanostructure of InN-rich InGaN epilayers. It is found that "seed" InGaN mosaic nanocrystallites are twisted with respect to the ensemble average and strain-free. The initial stages of InGaN-on-GaN epitaxial growth, therefore, conform to the Volmer-Weber growth mechanism with "seeds" nucleated on strain fields generated by the a-type edge dislocations. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3658619]
