Light emitting diode and method for improving luminescence efficiency thereof

Abstract

A light emitting diode comprising a semiconductor layer, a first electrode, a second electrode and a diamond-like carbon layer is provided. The semiconductor layer includes a first type doped semiconductor layer, a light emitting layer and a second type doped semiconductor layer. Wherein, the light emitting layer locates between the first type doped semiconductor layer and the second type doped semiconductor layer. The first electrode is electrically connected to the first type doped semiconductor layer. The second electrode is electrically connected to the second type doped semiconductor layer. The diamond-like carbon layer covers on the semiconductor layer and exposes at least a portion of the first electrode. Moreover, the exposed outer surface of the diamond-like carbon layer is a rough surface. Alternatively, other passivation layer with rough surface can be substituted for the diamond-like carbon layer.

1 . A light emitting diode, comprising: 
 a semiconductor layer including a first type doped semiconductor layer, a light emitting layer and a second type doped semiconductor layer, wherein the light emitting layer locates between the first type doped semiconductor layer and the second type doped semiconductor layer;    a first electrode electrically connecting to the first type doped semiconductor layer;    a second electrode electrically connecting to the second type doped semiconductor layer; and    a diamond-like carbon layer covering the semiconductor layer and exposes at least a portion of the first electrode.    
   
   
       2 . The light emitting diode according to  claim 1 , wherein the surface of the diamond-like carbon layer exposed is rough surface.  
   
   
       3 . The light emitting diode according to  claim 1 , further comprising a substrate, wherein the first type doped semiconductor layer is disposed on the substrate, the light emitting layer is disposed on a portion of the first type doped semiconductor layer, the second type doped semiconductor layer is disposed on the light emitting layer, the first electrode is disposed on the region of the first type doped semiconductor layer which the light emitting layer is not disposed thereon, the second electrode is disposed on the second type doped semiconductor layer, and part of the second electrode is further exposed by the diamond-like carbon layer.  
   
   
       4 . The light emitting diode according to  claim 3 , further comprising a first electric conductive layer disposing between the substrate and the first type doped semiconductor layer, and the first electrode electrically connects to the first electric conductive layer passing through the first type doped semiconductor layer.  
   
   
       5 . The light emitting diode according to  claim 4 , wherein the material of the first electric conductive layer includes transparent conductive material.  
   
   
       6 . The light emitting diode according to  claim 4 , further comprising a first optic reflective layer disposing between the substrate and the first electric conductive layer.  
   
   
       7 . The light emitting diode according to  claim 3 , further comprising a second electric conductive layer disposing on the second type doped semiconductor layer, and the second electrode is disposed on the second electric conductive layer.  
   
   
       8 . The light emitting diode according to  claim 7 , wherein the material of the second electric conductive layer includes transparent conductive material.  
   
   
       9 . The light emitting diode according to  claim 7 , further comprising a second optic reflective layer disposing on the second electric conductive layer, and the second electrode is disposed on the second optic reflective layer.  
   
   
       10 . The light emitting diode according to  claim 3 , wherein the substrate includes silicon substrate or metallic substrate.  
   
   
       11 . The light emitting diode according to  claim 1 , further comprising a semiconductor substrate disposing between the second electrode and the semiconductor layer.  
   
   
       12 . A light emitting diode, comprising: 
 a semiconductor layer including a first type doped semiconductor layer, a light emitting layer and a second type doped semiconductor layer, wherein the light emitting layer locates between the first type doped semiconductor layer and the second type doped semiconductor layer;    a first electrode electrically connecting to the first type doped semiconductor layer;    a second electrode electrically connecting to the second type doped semiconductor layer; and    a passivation layer covered on the semiconductor layer and exposes at least a portion of the first electrode, the exposed outer surface of the passivation layer is rough.    
   
   
       13 . The light emitting diode according to  claim 12 , further comprising a substrate, wherein the first type doped semiconductor layer is disposed on the substrate, the light emitting layer is disposed on a portion of the first type doped semiconductor layer, the second type doped semiconductor layer is disposed on the light emitting layer, the first electrode is disposed on the region of the first type doped semiconductor layer which the light emitting layer is not disposed thereon, the second electrode is disposed on the second type doped semiconductor layer, and part of the second electrode is further exposed by the passivation layer.  
   
   
       14 . The light emitting diode according to  claim 13 , further comprising a first electric conductive layer disposing between the substrate and the first type doped semiconductor layer, and the first electrode electrically connects to the first electric conductive layer passing through the first type doped semiconductor layer.  
   
   
       15 . The light emitting diode according to  claim 14 , wherein the material of the first electric conductive layer includes transparent conductive material.  
   
   
       16 . The light emitting diode according to  claim 14 , further comprising a first optic reflective layer disposing between the substrate and the first electric conductive layer.  
   
   
       17 . The light emitting diode according to  claim 13 , further comprising a second electric conductive layer disposing on the second type doped semiconductor layer, and the second electrode is disposed on the second electric conductive layer.  
   
   
       18 . The light emitting diode according to  claim 17 , wherein the material of the second electric conductive layer includes transparent conductive material.  
   
   
       19 . The light emitting diode according to  claim 17 , further comprising a second optic reflective layer disposing on the second electric conductive layer, and the second electrode is disposed on the second optic reflective layer.  
   
   
       20 . The light emitting diode according to  claim 13 , wherein the substrate includes silicon substrate or metallic substrate.  
   
   
       21 . The light emitting diode according to  claim 12 , further comprising a semiconductor substrate disposing between the second electrode and the semiconductor layer.  
   
   
       22 . A method for improving luminescence efficiency of a light emitting device, comprising the steps of: 
 providing a light emitting diode, the light emitting diode at least includes a semiconductor layer, a first electrode and a second electrode; and    forming a diamond-like carbon layer on the light emitting diode, the diamond-like carbon layer covers on the semiconductor layer and exposes at least a portion of the first electrode.    
   
   
       23 . The method for improving luminescence efficiency of a light emitting device according to  claim 22 , wherein after the diamond-like carbon layer is formed, further comprising proceeding a surface roughening step on the diamond-like carbon layer.  
   
   
       24 . The method for improving luminescence efficiency of a light emitting device according to  claim 23 , wherein the surface roughening step includes a reactive ion etching.  
   
   
       25 . A method for improving luminescence efficiency of a light emitting device, comprising the steps of: 
 providing a light emitting diode, the light emitting diode at least includes a semiconductor layer, a first electrode, a second electrode and a passivation layer, wherein the passivation layer covers on the semiconductor layer and exposes at least a portion of the first electrode; and    proceeding a surface roughening step on the passivation layer.    
   
   
       26 . The method for improving luminescence efficiency of a light emitting device according to  claim 25 , wherein the surface roughening step includes a reactive ion etching.