 This paper discusses the origin of visible emission centers and ZnO nanorods grown with different approaches and fabricates wide-light emitting diodes, LEDs, by combining nZnO nanorods and hollow nanotubes with different p-type materials to form heterojunctions, analyzing their optical, electrical, and electrooptical characteristics with an emphasis on the deep-level centers that cause the emission. This article was authored by Magnus Willender, Omer Neuer, Jamil Ranasadhaf, and others.