Ga 0.5 In 0.5 P is a solid solution of special importance, which is almost lattice matched to GaAs. This allows, in combination with (Al x Ga 1−x) 0.5 In 0.5, the growth of lattice matched quantum wells for red emitting semiconductor lasers, e.g., red emitting (650 nm) RCLEDs or VCSELs for PMMA plastic optical fibers.