Semiconductor light emitting device
Disclosed is a semiconductor light emitting device including: a plurality of semiconductor layers; a first non-conductive reflective film formed on the plurality of semiconductor layer to reflect light from the active layer, wherein the first non-conductive reflective film includes multiple layers and has a first incident angle as the Brewster angle; a second non-conductive reflective film formed on the first non-conductive reflective film to reflect light transmitted through the first non-conductive reflective film, wherein the second non-conductive reflective film includes multiple layers, with part of which being made of a different material from the first non-conductive reflective film, and has a second incident angle as the Brewster angle, different from the first incident angle; and an electrode electrically connected to one of the plurality of semiconductor layers.
1. A semiconductor light emitting device comprising:
a plurality of semiconductor layers, which includes a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type different from the first conductivity type, and an active layer interpositioned between the first and second semiconductor layers and adapted to generate light by electron-hole recombination;
a first non-conductive reflective film formed on the plurality of semiconductor layer to reflect light from the active layer, wherein the first non-conductive reflective film includes multiple layers and has a first incident angle as the Brewster angle;
a second non-conductive reflective film formed on the first non-conductive reflective film to reflect light transmitted through the first non-conductive reflective film, wherein the second non-conductive reflective film includes multiple layers, with part of the second non-conductive reflective film made of a different material from the first non-conductive reflective film, and the second non-conductive reflective film has a second incident angle as the Brewster angle, the second incident angle different from the first incident angle; and
an electrode electrically connected to one of the plurality of semiconductor layers;
wherein the second non-conductive film has a higher reflectance at the Brewster angle of the first non-conductive reflective film than at other angles.
2. The semiconductor light emitting device according to claim 1 , wherein the first non-conductive reflective film and the second non-conductive reflective film each comprise one of a DBR (Distributed Bragg Reflector) and an ODR (Omni-Directional Reflector).
3. The semiconductor light emitting device according to claim 1 , wherein the multiple layers of the first non-conductive reflective film comprise a stack of alternating first material layer/second material layer pairs, and
the multiple layers of the second non-conductive reflective film comprise a stack of alternating third material layer/fourth material layer pairs, wherein at least one of the third material layer and the fourth material layer is made of a different material from the first material layer and the second material layer.
4. The semiconductor light emitting device according to claim 3 , wherein the first and second material layers comprise different materials selected from SiO 2 , TiO 2 , Ta 2 O 2 , HfO, ZrO and SiN, and
the third and fourth material layers comprise different materials selected from TiO 2 , Ta 2 O 5 , HfO, ZrO and SiN.
5. The semiconductor light emitting device according to claim 3 , wherein the first material layer/second material layer pair comprises SiO 2 /TiO 2 to form a first insulating reflective layer, and
the third material layer/fourth material layer pair comprises TiO 2 /Ta 2 O 5 to form a second insulating reflective layer.