Abstract: There is provided a white light illumination system including a radiation source, a first luminescent material having a peak emission wavelength of about 570 to about 620 nm, and a second luminescent material having a peak emission wavelength of about 480 to about 500 nm, which is different from the first luminescent material. The LED may be a UV LED and the luminescent materials may be a blend of two phosphors. The first phosphor may be an orange emitting Eu2+, Mn2+ doped strontium pyrophosphate, (Sr0.8Eu0.1Mn0.1)2P2O7. The second phosphor may be a blue-green emitting Eu2+ doped SAE, (Sr0.90-0.99Eu0.01-0.1)4Al14O25. A human observer perceives the combination of the orange and the blue-green phosphor emissions as white light.

Abstract: An optoelectronic device with a Group III Nitride active layer is disclosed that comprises a silicon carbide substrate; an optoelectronic diode with a Group III nitride active layer; a buffer structure selected from the group consisting of gallium nitride and indium gallium nitride between the silicon carbide substrate and the optoelectronic diode; and a stress-absorbing structure comprising a plurality of predetermined stress-relieving areas within the crystal structure of the buffer structure, so that stress-induced cracking that occurs in the buffer structure occurs at predetermined areas rather than elsewhere in the buffer structure.