1. A group III nitride semiconductor heterostructure comprising: a short period superlattice comprising a plurality of quantum wells alternating with a plurality of barriers, wherein the plurality quantum wells comprise a semiconductor material having a first band gap and the plurality of barriers comprise a semiconductor material having a second band gap wider than the first band gap, and wherein at least one of: the plurality of quantum wells or the plurality of barriers includes a carbon doped layer including a plurality of openings.