A semiconductor light emitter includes a quantum well active layer which includes
nitrogen and at least one other Group-V element, and barrier layers which are provided
alongside the quantum well active layer, wherein the quantum well active layer
and the barrier layers together constitute an active layer, wherein the barrier
layers are formed of a Group-III-V mixed-crystal semiconductor that includes nitrogen
and at least one other Group-V element, a nitrogen composition thereof being smaller
than that of the quantum well active layer.
