InGaN epilayer characterization by microfocused x-ray reciprocal space mapping

Kachkanov, V. and Dolbnya, I.P. and O'Donnell, Kevin and Martin, Robert and Edwards, Paul and Pereira, S. (2011) InGaN epilayer characterization by microfocused x-ray reciprocal space mapping. Applied Physics Letters, 99 (18). ISSN 0003-6951

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    Abstract

    We report the use of microfocused three-dimensional x-ray reciprocal space mapping to study InGaN epilayers with average InN content 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.