Group iii nitride based led structures including multiple quantum wells with barrier-well unit interface layers

A light emitting diode comprising:

• an active region comprising a plurality of sequentially arranged barrier-well units;
• wherein the plurality of sequentially arranged barrier-well units comprises at least one barrier-well unit of a first type, and each barrier-well unit of the first type comprises a Group III nitride barrier layer comprising a first bandgap, a Group III nitride well layer comprising a second bandgap, a first Group III nitride interface layer comprising a third bandgap, and a second Group III nitride interface layer comprising a fourth bandgap;
• wherein the first Group III nitride interface layer comprises a substantially continuous variation of composition with respect to thickness of the first Group III nitride interface layer;
• and
• wherein the second Group III nitride interface layer comprises a substantially continuous variation of composition with respect to thickness of the second Group III nitride interface layer.