Light emitting diode having distributed bragg reflector

Abstract

A light-emitting diode (LED) includes a light-emitting structure arranged on a first surface of a substrate, the light-emitting structure including a first conductivity-type semiconductor layer; a second conductivity-type semiconductor layer, and an active layer interposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer. The LED includes a first distributed Bragg reflector arranged on a second surface of the substrate opposite to the first surface, the first distributed Bragg reflector including a first laminate structure including alternately stacked SiO 2 and Nb 2 O 5 layers. The first laminate structure of the first distributed Bragg reflector is configured to reflect at least 90% of a first wavelength range of blue light emitted from the light emitting structure.

What is claimed is: 
     
         1 . A light-emitting diode (LED), comprising:
 a light-emitting structure arranged on a first surface of a substrate, the light-emitting structure comprising:
 a first conductivity-type semiconductor layer; 
 a second conductivity-type semiconductor layer; and 
 an active layer interposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer; and 
   a first distributed Bragg reflector arranged on a second surface of the substrate opposite to the first surface, the first distributed Bragg reflector comprising a first laminate structure comprising alternately stacked silicon dioxide (SiO 2 ) and niobium pentoxide (Nb 2 O 5 ) layers,   wherein the first laminate structure of the first distributed Bragg reflector is configured to reflect at least 90% of a first wavelength range of blue light emitted from the light-emitting structure.   
     
     
         2 . The LED of  claim 1 , wherein the first laminate structure of the first distributed Bragg reflector is further configured to reflect at least 90% of a second wavelength range of green light and at least 90% of a third wavelength range of red light. 
     
     
         3 . The LED of  claim 1 , wherein the first laminate structure of the first distributed Bragg reflector comprises an uppermost layer and a lowermost layer comprising SiO 2 . 
     
     
         4 . The LED of  claim 1 , further comprising:
 a first electrode connected to the first conductivity-type semiconductor layer; and   a second electrode connected to the second conductivity-type semiconductor layer.   
     
     
         5 . The LED of  claim 4 , further comprising:
 a metal layer located under the first distributed Bragg reflector.   
     
     
         6 . The LED of  claim 4 , further comprising:
 a second distributed Bragg reflector arranged on the light-emitting structure, wherein the light-emitting structure is interposed between the second distributed Bragg reflector and the substrate.   
     
     
         7 . The LED of  claim 6 , wherein the second distributed Bragg reflector comprises a second laminate structure comprising alternately stacked SiO 2  and Nb 2 O 5  layers. 
     
     
         8 . The LED of  claim 7 , wherein the second laminate structure of the second distributed Bragg reflector is configured to:
 allow a fourth wavelength range of blue light generated in the active layer to pass through the second Distributed Bragg reflector, and   reflect a fifth wavelength range of non-blue light.   
     
     
         9 . The LED of  claim 6 , further comprising a transparent conductive layer interposed between the second conductivity-type semiconductor layer and the second distributed Bragg reflector. 
     
     
         10 . The LED of  claim 9 , the transparent conductive layer comprises indium tin oxide (ITO) or zinc oxide (ZnO). 
     
     
         11 . The LED of  claim 6 , wherein the second distributed Bragg reflector covers at least a portion of the first conductivity-type semiconductor layer and has an opening exposing the first conductivity-type semiconductor layer. 
     
     
         12 . A light-emitting diode (LED), comprising:
 a substrate comprising a pattern on a first surface of the substrate;   a light-emitting structure disposed on the first surface of the substrate, the light-emitting structure comprising:
 a first conductivity-type semiconductor layer; 
 a second conductivity-type semiconductor layer; and 
 an active layer disposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer; 
   a first electrode connected to the first conductivity-type semiconductor layer;   a second electrode connected to the second conductivity-type semiconductor layer;   a first distributed Bragg reflector (DBR) disposed on a second surface of the substrate opposite to the first surface; and   a second DBR disposed on the light-emitting structure having the light-emitting structure disposed between the second DBR and the substrate, the second DBR comprises a first opening exposing the first electrode and a second opening exposing the second electrode,   wherein the first DBR and the second DBR comprise niobium pentoxide (Nb 2 O 5 ).   
     
     
         13 . The LED of  claim 12 , wherein:
 the first DBR comprises a first laminate structure comprising a plurality of silicon dioxide (SiO 2 ) layers and a plurality of Nb 2 O 5  layers,   the first laminate structure is configured to reflect a first wavelength range of blue light generated in the active layer.   
     
     
         14 . The LED of  claim 12 , wherein the second DBR comprises a second laminate structure comprising a plurality of SiO 2  layers and a plurality layers of Nb 2 O 5  layers. 
     
     
         15 . The LED of  claim 12 , wherein the second DBR covers a portion of an upper surface of the first conductivity-type semiconductor layer, a portion of a side surface of the second conductivity-type semiconductor layer, and a portion of a side surface of the active layer. 
     
     
         16 . The LED of  claim 12 , wherein the second DBR has an opening exposing the first conductivity-type semiconductor layer. 
     
     
         17 . The LED of  claim 16 , wherein the first electrode is connected to the first conductivity-type semiconductor layer through the opening of the second DBR.