Light emitting diode

A light emitting diode comprising:

• a first conductivity type semiconductor layer having a front side and a back side;
• a second conductivity type semiconductor layer having a front side and a back side;
• an active layer formed between the back side of the first conductivity type semiconductor layer and the front side of the second conductivity type semiconductor layer;
• a second conductivity type reflective layer formed on the back side of the second conductivity type semiconductor layer;
• a reflective part formed on the back side of the second conductivity type reflective layer opposite the second conductivity type semiconductor layer to reflect light of a short wavelength (UVA wavelength) band and light of a blue wavelength band;
• the reflective part electrically connected to the second conductivity type semiconductor layer wherein the second conductivity type reflective layer comprises distributed bragg reflector (DBR) unit layers for reflecting light of a short wavelength (UVA wavelength) band of 315 nm to 420 nm, each of the DBR unit layers comprises a low refractive index layer and a high refractive index layer adjacent to the low refractive index layer;
• the low refractive index layer and the high refractive index layer comprise AlxGa1-xN (0<x≦1) and AlyGa1-yN (0≦y<1, y<x), respectively;
• and
• the DBR unit layers are repeated in at least triplicate in the second conductivity type reflective layer, and when the total doping concentration of the second conductivity type dopant in the initial three DBR unit layers placed closest to the back side of the second conductivity type semiconductor layer and the total doping concentration of the second conductivity type dopant in the other DBR unit layers are defined as first and second doping concentrations, respectively, the first doping concentration is lower than the second doping concentration.