Review: Semiconductors emitting light in the blue or green will have many very interesting applications, e.g. in full-color displays or miniaturized printers. Remarkable recent progress in research on InGaAlN and II-VI systems is reviewed, from the viewpoint of making reliable light-emitting devices, including fabrication processes such as epitaxial growth and doping. The Figure shows a GaN him grown on sapphire and etched by the reactive fast atom beam technique.