Characterization of InGaN quantum disks in GaN nanowires.

Catalyst-free GaN nanowires with InGaN quantum disks (QDs) were characterized by scanning/transmission electron microscopy (S/TEM) and photoluminescence. A variety of structures, from QDs with large strain fields to apparently strain free QDs were observed. TEM lattice imaging revealed dislocations in the QD regions of the samples. Stacking faults were also observed and appear to be associated with the GaN growth temperature rather than the presence of indium. Energy dispersive X-ray spectroscopy in the TEM revealed indium concentrated in stacking faults but not always localized in the QD regions. Photoluminescence spectra show a red-shift, possibly associated with indium concentration. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]