Abstract: A color tunable light emission diode in which the color tone of the emission color changes by controlling the injection current, which has an active layer sandwiched between a p-type layer and an n-type layer on a substrate, and the active color layer is formed by doping Eu and Mg to an AlGaInN-based material which is GaN, InN, AlN or a mixed crystal of any two or more of them; and a micro LED display, wherein its display unit is formed by integrating image pixels having the above color tunable light emission diode are provided; and a light emitting semiconductor device technology capable of providing an ultra-small and high definition micro LED display can be provided.