Abstract: A diamond based Blue/UV light emitting source is disclosed. The source includes a diamond substrate having a first conductivity type, a first aluminum gallium nitride layer above the diamond substrate having the same conductivity type as the substrate, a bulk or a quantum well structure on the AlGaN layer formed of a plurality of repeating sets of alternating layers selected from among GaN, InGaN, and AlInGaN, a second AlGaN layer on the quantum well or the bulk active layer having the opposite conductivity type as the first AlGaN layer, a contact structure on the second AlGaN layer having the opposite conductivity type from the substrate and the first AlGaN layer, an ohmic contact to the diamond substrate, and an ohmic contact to the contact structure.