Single Chip White LEDs

The operation principles of the various single chip luminescence conversion (LUCO).white LEDs, that can be realized with blue or ultraviolet (UV) LED chips, are briefly reviewed. In order to demonstrate the feasibility of the so far almost unexplored case of UV pumped tricolor LUCO white LEDs, In x Ga 1-x N single quantum well LED layer sequences were grown by MOCVD and processed into near-UV LED pump chips. Europium doped oxide and sulfide phosphors emitting in the blue, the green and the red spectral range were used for UV to visible conversion. With white blends prepared from these phosphors, housed white LEDs with high color quality were realized.