Spectrally and time-resolved cathodoluminescence microscopy of semipolar InGaN SQW on (1122) and (1011) pyramid facets

摘要

Semipolar InGaN/GaN single quantum wells (SQWs) grown on {1122} planes of an inverted pyramid surface and {1011} 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.