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Spectrally and time-resolved cathodoluminescence microscopy of semipolar InGaN SQW on (11equation image2) and (10equation image1) pyramid facets



Semipolar InGaN/GaN single quantum wells (SQWs) grown on {11equation image2} planes of an inverted pyramid surface and {10equation image1} facets of single self assembled pyramids have been studied by spatially, spectrally, and time-resolved cathodoluminescence (CL) microscopy. Mappings of local spectra and local transients provide the distribution of spectral and time-resolved luminescence properties by peak wavelength images, time delayed CL images (TDCLIs), and initial lifetime maps. The SQW on inverse pyramids exhibit strong local differences in recombination kinetics – two orders of magnitude change in initial lifetime – correlated with a giant shift in emission energy of ∼1 eV along a facet. For single pyramids a migration process of indium adatoms from the upper facet to the edges leads to an emission of longer wavelengths at the edges and shorter wavelengths at the upper facet with respect to the base.