A semiconductor light emitting device includes a light emitting layer disposed between an n-type region and a p-type region. The light emitting layer may be a wurtzite III-nitride layer with a thickness of at least 50 angstroms. The light emitting layer may have a polarization reversed from a conventional wurtzite III-nitride layer, such that across an interface between the light emitting layer and the p-type region, the wurtzite c-axis points toward the light emitting layer. Such an orientation of the c-axis may create a negative sheet charge at an interface within or at the edge of the p-type region, providing a barrier to charge carriers in the light emitting layer.