A light-emitting semiconductor device comprises a III-Nitride active region and
a III-Nitride layer formed proximate to the active region and having a thickness
that exceeds a critical thickness for relaxation of strain in the III-Nitride layer.
The III-Nitride layer may be a carrier confinement layer, for example. In another
aspect of the invention, a light-emitting semiconductor device comprises a III-Nitride
light emitting layer, an InxAlyGa1-x-yN (0x1,
0y1, x+y1), and a spacer layer interposing the light emitting
layer and the InxAlyGa1-x-yN layer. The spacer
layer may advantageously space the InxAlyGa1-x-yN
layer and any contaminants therein apart from the light emitting layer. The composition
of the III-Nitride layer may be advantageously selected to determine a strength
of an electric field in the III-Nitride layer and thereby increase the efficiency
with which the device emits light.