Origin of the fluctuations in the luminescence emission in InGaN quantum wells

InGaN single quantum wells grown by metal organic vapour phase epitaxy were studied by spectrally resolved cathodoluminescence (CL) and transmission electron microscopy (TEM). Spatial fluctuations of the intensity and peak wavelength at submicrometric scale in the CL emission were observed. The correlation of CL data with structural analysis carried out by TEM shows that such fluctuations are related to threading dislocations that cross the full structure and modify In concentration and thereafter the piezoelectric field and the non-radiative recombination efficiency.