Cathodoluminescence Spectroscopy And Imaging Of Gan/(Al,Ga)N Nanocolumns Containing Quantum Disks

Using spatially resolved cathodoluminescence spectroscopy, the authors have measured the spectral and spatial distribution of the luminescence intensity of GaN/(Al,Ga)N nanocolumns containing quantum disks. The optical emission of the quantum disk and of the thick (Al,Ga)N layer in the columns were clearly identified. The disk spectra of single columns are as broad as 80 meV. A significant contribution to this broadening is probably due to the laterally inhomogeneous strain distribution within the disks. The optical emission of the thick (Al,Ga)N layer in the columns is spread out over a wide spectral range of several 100 meV, which is caused by an inhomogeneous incorporation of Al along the growth direction of the columns. (c) 2007 American Institute of Physics.