An optical semiconductor device with a multiple quantum well structure, in which well layers and barrier layers comprising various types of semiconductor layers are alternately layered, in which device well layers (6a) of a first composition based on a nitride semiconductor material with a first electron energy and barrier layers (6b) of a second composition of a nitride semiconductor material with electron energy which is higher in comparison with the first electron energy are provided, followed, seen in the direction of growth, by a radiation-active quantum well layer (6c), for which the essentially non-radiating well layers (6a) and the barrier layers (6b) arranged in front form a superlattice.