A light-emitting device including a substrate, three-dimensional semiconductor elements resting on the substrate, at least one shell at least partially covering the lateral walls of the semiconductor element, the shell including an active area having multiple quantum wells, and an electrode at least partially covering the shell, at least a portion of the active area being sandwiched between the electrode and the lateral walls of the semiconductor element. The active area includes an alternation of first semiconductor layers mainly including a first element and a second element and of second semiconductor layers mainly including the first element and the second element and further including a third element. In at least three of the layers, the mass concentration of the third element increases in the portion of the active layer as the distance to the substrate decreases.