Cathodoluminescence study of InxGa1-xN quantum wells

We studied the cathodoluminescence spectra of InxGa1-xN, focusing on the spatial variation of the spectra. Strong inhomogeneity of cathodoluminescence spectra was observed on 22 nm thick InxGa1-xN layers, where the peak energy varied up to 400 meV. In a double quantum well with a well width of 10 Angstrom, the luminescence peak in a broad area spectrum was at 3.18 eV, but on some areas the peak was at 3.07 eV, the size of the area being about 1 mum. The variation of the cathodoluminescence spectra clearly indicates the presence of in-plane potential fluctuation in some InxGa1-xN samples, although the cathodoluminescence spectra of most of our quantum wells optimized for devices were found to be uniform at least within the spatial resolution limit. (C) 2001 American Institute of Physics.