F. Güell, J. O. Osso, A. R. Goñi, A. Cornet, J. R. Morante "Direct imaging of the visible emission bands from individual ZnO nanowires by near-field optical spectroscopy" Nanotechnology 20, 31, pp. - 2009 DOI: 10.1088/0957-4484/20/31/315701