Light emitting device having vertically stacked light emitting diodes

Abstract

Exemplary embodiments of the present invention relate to a light emitting device including a first light emitting cell including a lower light emitting diode and an upper light emitting diode vertically stacked on a substrate and at least three electrodes arranged on the first light emitting cell. Each of the lower light emitting diode and the upper light emitting diode includes an active layer disposed between a lower semiconductor layer and an upper semiconductor layer, the lower semiconductor layer being disposed between the substrate and the upper semiconductor layer.

What is claimed is: 
     
         1 . A light emitting device, comprising:
 a first light emitting cell comprising a lower light emitting diode and an upper light emitting diode vertically stacked on a substrate; and   at least three electrodes arranged on the first light emitting cell,   wherein each of the lower light emitting diode and the upper light emitting diode comprises an active layer disposed between a lower semiconductor layer and an upper semiconductor layer, the lower semiconductor layer being disposed between the substrate and the upper semiconductor layer, and   wherein a first electrode of the at least three electrodes is arranged on an exposed region of the lower semiconductor layer of the lower light emitting diode, a second electrode of the at least three electrodes is arranged on an exposed region of the upper semiconductor layer of the lower light emitting diode, and a third electrode of the at least three electrodes is arranged on an exposed region of the upper semiconductor layer of the upper light emitting diode.   
     
     
         2 . The light emitting device of  claim 1 , further comprising a wire connecting the first electrode and the third electrode. 
     
     
         3 . The light emitting device of  claim 1 , wherein the substrate comprises sapphire or SiC. 
     
     
         4 . The light emitting device of  claim 1 , further comprising a buffer layer disposed between the substrate and the lower light emitting diode. 
     
     
         5 . The light emitting device of  claim 1 , wherein the first electrode comprises indium tin oxide (ITO). 
     
     
         6 . The light emitting device of  claim 1 , wherein the upper semiconductor layer of the lower light emitting diode and the lower semiconductor layer of the upper light emitting diode are electrically connected to each other. 
     
     
         7 . The light emitting device of  claim 6 , wherein the upper semiconductor layer of the lower light emitting diode and the lower semiconductor layer of the upper light emitting diode comprise the same material. 
     
     
         8 . The light emitting device of  claim 6 , wherein the upper semiconductor layer of the lower light emitting diode and the lower semiconductor layer of the upper light emitting diode comprise different materials. 
     
     
         9 . The light emitting device of  claim 1 , further comprising:
 a second light emitting cell spaced apart from the first light emitting cell on the substrate, the second light emitting cell comprising the same vertically stacked structure as the first light emitting cell,   wherein the first light emitting cell and the second light emitting cell are electrically connected to each other by a wire.   
     
     
         10 . The light emitting device of  claim 9 , further comprising:
 at least three electrodes arranged on the second light emitting cell,   wherein the wire connects the first electrode of the first light emitting cell to a second electrode of the at least three electrodes arranged on the second light emitting cell.   
     
     
         11 . A light emitting device, comprising:
 a first light emitting cell, comprising:
 a lower light emitting diode disposed on a substrate, the lower light emitting diode comprising a lower semiconductor layer and an upper semiconductor layer; and 
 an upper light emitting diode disposed on the lower light emitting diode; 
   a first electrode disposed on a portion of the lower semiconductor layer;   a second electrode disposed on a portion of the upper semiconductor layer; and   a third electrode disposed on a portion of the upper light emitting diode.   
     
     
         12 . The light emitting device of  claim 11 , further comprising a wire connecting the first electrode to the third electrode. 
     
     
         13 . The light emitting device of  claim 11 , wherein the substrate comprises sapphire or SiC. 
     
     
         14 . The light emitting device of  claim 11 , further comprising a buffer layer disposed between the substrate and the lower light emitting diode. 
     
     
         15 . The light emitting device of  claim 11 , wherein the first electrode comprises indium tin oxide (ITO). 
     
     
         16 . The light emitting device of  claim 11 , further comprising:
 a second light emitting cell spaced apart from the first light emitting cell on the substrate, the second light emitting cell comprising the same vertically stacked structure as the first light emitting cell,
 wherein the first light emitting cell and the second light emitting cell are electrically connected to each other by a wire. 
   
     
     
         17 . The light emitting device of  claim 16 , further comprising:
 at least three electrodes arranged on the second light emitting cell,   wherein the wire connects the first electrode of the first light emitting cell to a second electrode of the at least three electrodes arranged on the second light emitting cell.