LIGHT EMITTING DIODE WITH ZnO EMITTER

Abstract

A light emitting diode (LED) includes a p-type ohmic contact and a p-type substrate in contact with the p-type ohmic contact. A p-type confinement layer is provided on the p-type substrate. An emission layer is provided on the p-type confinement layer. An n-type confinement layer is provided on the emission layer. A transparent II-VI n-type contact layer is formed on the n-type confinement layer as a replacement for a current spreading layer, a III-V contact layer and an n-type ohmic contact.

1 . A method for forming a light emitting diode (LED), comprising:
 providing a p-type ohmic contact, a p-type substrate in contact with the p-type ohmic contact, a p-type confinement layer on the p-type substrate, a GaInP emission layer on the p-type confinement layer and an n-type confinement layer on the emission layer; and   forming a transparent zinc oxide n-type contact layer directly on the n-type confinement layer as a replacement for a current spreading layer, a III-V contact layer and an n-type ohmic contact.   
     
     
         2 . The method as recited in  claim 1 , wherein the zinc oxide contact layer includes Al doped zinc oxide. 
     
     
         3 . The method as recited in  claim 1 , wherein forming the transparent zinc oxide n-type contact layer includes forming the transparent zinc oxide n-type contact layer to a thickness of between about 200 nm to about 700 nm. 
     
     
         4 . The method as recited in  claim 1 , wherein the LED is produces red light. 
     
     
         5 . The method as recited in  claim 1 , wherein forming the transparent zinc oxide n-type contact layer includes forming an amorphous phase. 
     
     
         6 . The method as recited in  claim 1 , wherein the emission layer includes AlGaInP. 
     
     
         7 . A method for forming a light emitting diode (LED) comprising the steps of:
 forming a p-type ohmic contact on one side of a p-doped substrate;   forming a p-type confinement layer on a side opposite to the p-type ohmic contact;   forming an emission layer on the p-type confinement layer;   forming an n-type confinement layer on the emission layer; and   forming an n-type contact layer on the n-type confinement layer, the n-type confinement layer including a single unitary layer configured to function as all of a current spreading layer, a III-V contact layer, and an n-type ohmic contact.   
     
     
         8 . The method as recited in  claim 7 , wherein forming the n-type contact layer includes forming the n-type contact layer of a II-VI type material. 
     
     
         9 . The method as recited in  claim 8 , wherein the II-VI material includes ZnO. 
     
     
         10 . The method a recited in  claim 7 , wherein the n-type contact layer includes a doped form of transparent II-VI material. 
     
     
         11 . The method as recited in  claim 10 , wherein a dopant included in the doped form is selected from the group consisting of Al, B, Ga, and In. 
     
     
         12 . The method as recited in  claim 7 , wherein the forming of the n-type contact layer includes forming the n-type contact layer between about 200 nm to about 700 nm in thickness. 
     
     
         13 . The method as recited in  claim 7 , wherein the p-type confinement layer and the n-type confinement layer include about a same thickness. 
     
     
         14 . The method as recited in  claim 7 , wherein the LED includes a red LED. 
     
     
         15 . A method of forming a red light emitting diode (LED), comprising the steps of:
 forming a p-type ohmic contact in direct contact with a p-type substrate;   forming a p-type confinement layer directly on the p-type substrate on a side opposite the p-type ohmic contact;   forming an emission layer on the p-type confinement layer;   forming an n-type AlInP confinement layer on the emission layer, the n-type and p-type confinement layers being symmetrically disposed relative to the emission layer; and   forming a transparent II-VI n-type amorphous contact layer formed directly on the n-type confinement layer and configured to function as all of a current spreading layer, a III-V contact layer and an n-type ohmic contact.   
     
     
         16 . The method as recited in  claim 15 , wherein the forming of transparent II-VI n-type amorphous contact layer includes forming ZnO. 
     
     
         17 . The method as recited in  claim 15 , wherein a doping element is deposited on the transparent II-VI n-type amorphous contact layer and then annealed to cause diffusion of the doping element into the transparent II-VI n-type amorphous contact layer. 
     
     
         18 . The method as recited in  claim 15 , wherein the transparent II-VI n-type amorphous contact layer includes a thickness between about 200 nm and about 700 nm. 
     
     
         19 . The method as recited in  claim 15 , wherein the n-type confinement layer and the p-type confinement layers are formed to about a same thickness. 
     
     
         20 . The method as recited in  claim 15 , wherein the n-type confinement layer and the p-type confinement layer are formed with III-V materials.