Light emitting device

Abstract

A light emitting device (LED) is provided. The LED comprises a light emitting structure and a mixed-period photonic crystal structure. The light emitting structure comprises a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer. The mixed-period photonic crystal structure is on the light emitting structure.

1 - 20 . (canceled) 
   
   
       21 . A light emitting device (LED), comprising:
 a light emitting structure comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer; and   a mixed-period photonic crystal structure on the light emitting structure.   
   
   
       22 . The LED of  claim 21 , wherein the mixed-period photonic crystal structure comprises:
 a first photonic crystal structure having a first period in a partial region of the first conductivity type semiconductor layer; and   a second photonic crystal structure having a second period in the partial region of the first conductivity type semiconductor layer that includes the first photonic crystal structure.   
   
   
       23 . The LED of  claim 22 , wherein the second period is smaller than the first period. 
   
   
       24 . The LED of  claim 23 , wherein the second period is non-uniform. 
   
   
       25 . The LED of  claim 23 , wherein the second period is uniform. 
   
   
       26 . The LED of  claim 23 , wherein the second period is about 100 nm to about 800 nm. 
   
   
       27 . The LED of  claim 21 , further comprising an undoped semiconductor layer on the first conductivity type semiconductor layer. 
   
   
       28 . The LED of  claim 27 , wherein the mixed-period photonic crystal structure comprises:
 a first photonic crystal structure having a first period in a partial region of the undoped semiconductor layer; and   a second photonic crystal structure having a second period in the partial region of the undoped semiconductor layer that includes the first photonic crystal structure.   
   
   
       29 . The LED of  claim 21 , further comprising a nonconductive substrate on a side of the light emitting structure that is opposite to a side of the light emitting structure with the mixed-period photonic crystal structure. 
   
   
       30 . The LED of  claim 29 , wherein the mixed-period photonic crystal structure is on the second conductivity type semiconductor layer. 
   
   
       31 . A light emitting device (LED), comprising:
 a light emitting structure comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;   a conductive substrate on the light emitting structure; and   a mixed-period photonic crystal structure on the conductive substrate.   
   
   
       32 . The LED of  claim 31 , wherein the mixed-period photonic crystal structure comprises:
 a first photonic crystal structure having a first period in a partial region of the conductive substrate; and   a second photonic crystal structure having a second period in the partial region of the conductive substrate that includes the first photonic crystal structure.   
   
   
       33 . The LED of  claim 32 , wherein the second period is smaller than the first period. 
   
   
       34 . The LED of  claim 32 , wherein the second period is non-uniform. 
   
   
       35 . The LED of  claim 32 , wherein the second period is uniform. 
   
   
       36 . The LED of  claim 33 , wherein the first period is about 400 nm to about 3,000 nm and the second period is about 100 nm to about 800 nm. 
   
   
       37 . The LED of  claim 31 , further comprising a first electrode on a portion of the conductive substrate without the mixed-period photonic crystal structure. 
   
   
       38 . The LED of  claim 37 , wherein the first electrode comprises at least one of an ohmic contact layer, a reflection layer, and a coupling layer. 
   
   
       39 . The LED of  claim 31 , further comprising a second electrode layer on the second conductivity type semiconductor layer. 
   
   
       40 . The LED of  claim 39 , wherein the second electrode layer comprises at least one of an ohmic contact layer, a reflection layer, a coupling layer, and a second substrate. 
   
   
       41 . The LED of  claim 31 , wherein the conductive substrate comprises at least one of gallium nitride, gallium oxide, zinc oxide, silicon carbide, and a metal oxide. 
   
   
       42 . The LED of  claim 31 , wherein the conductive substrate is polished to a thickness of about 70 μm to about 100 μm.