Vertical geometry InGaN LED

Abstract

A vertical geometry light emitting diode is disclosed that is capable of emitting light in the red, green, blue, violet and ultraviolet portions of the electromagnetic spectrum. The light emitting diode includes a conductive silicon carbide substrate, an InGaN quantum well, a conductive buffer layer between the substrate and the quantum well, a respective undoped gallium nitride layer on each surface of the quantum well, and ohmic contacts in a vertical geometry orientation.

That which is claimed is: 
     
       1. A vertical geometry light emitting diode that is capable of emitting light in the electromagnetic spectrum, said light emitting diode comprising:
 a conductive silicon carbide substrate;   an InGaN quantum well;   a conductive buffer layer between said substrate and said quantum well;   a respective undoped gallium nitride layer on each surface of said quantum well;   ohmic contacts in a vertical geometry orientation;   a doped layer of gallium nitride between said buffer and said undoped gallium nitride layer;   an undoped layer of aluminum gallium nitride on the surface of said undoped gallium nitride layer on said quantum well that is opposite from said substrate and buffer; and   a doped layer of aluminum gallium nitride on said undoped aluminum gallium nitride layer.   
     
     
       2. A vertical geometry light emitting diode according to  claim 1  and further comprising a doped gallium nitride layer on said doped aluminum gallium nitride layer. 
     
     
       3. A vertical geometry light emitting diode according to  claim 2  wherein: said substrate, said buffer layer and said gallium nitride layer adjacent said buffer are all n-type; and
 said doped layer of aluminum gallium nitride and doped layer of gallium nitride thereon are p-type. 
 
     
     
       4. A vertical geometry light emitting diode according to  claim 1  wherein said quantum well comprises a multiple quantum well. 
     
     
       5. A pixel that includes a light emitting diode according to  claim 1 . 
     
     
       6. A display that includes a plurality of pixels according to  claim 5 . 
     
     
       7. A light emitting diode comprising:
 a p-type GaN layer;   a quantum well; and   an undoped GaN layer between the p-type GaN layer and the quantum well;   an undoped AlGaN layer on a surface of said undoped GaN layer between the undped GaN layer and the p-type GaN layer; and   a p-type AlGaN layer on said undoped AlGaN layer between said undoped AlGaN layer and said p-type GaN layer.   
     
     
       8. A light emitting diode according to claim 7, wherein the undoped GaN layer is directly on the quantum well and the undoped AlGaN layer. 
     
     
       9. A light emitting diode according to claim 7, wherein the undoped AlGaN layer has a thickness of about 30 Angstroms to about 50 Angstroms. 
     
     
       10. A light emitting diode according to claim 7, wherein the undoped GaN layer has a thickness of about 20 Angstroms to about 30 Angstroms. 
     
     
       11. A light emitting diode according to claim 7, further comprising a second undoped GaN layer, wherein the quantum well is between the second undoped GaN layer and the undoped GaN layer. 
     
     
       12. A vertical geometry light emitting diode according to claim 7, wherein said quantum well comprises a multiple quantum well. 
     
     
       13. A vertical geometry light emitting diode according to claim 7, wherein said quantum well comprises a single quantum well. 
     
     
       14. A pixel that includes a light emitting diode according to claim 7. 
     
     
       15. A display that includes a plurality of pixels according to claim 14. 
     
     
       16. A light emitting diode comprising:
 an n-type GaN layer;   a p-type GaN layer on the n-type GaN layer;   a quantum well between the p-type GaN layer and the n-type GaN layer;   a first undoped GaN layer directly on the quantum well between the p-type GaN layer and the quantum well;   an undoped AlGaN layer directly on the first undoped GaN layer wherein the first undoped GaN layer is between the undoped AlGaN layer and the quantum well; and   a p-type AlGaN layer on the undoped AlGaN layer between the undoped AlGaN layer and the p-type GaN layer.   
     
     
       17. A light emitting diode according to claim 16, further comprising a second undoped GaN layer between the quantum well and the n-type GaN layer. 
     
     
       18. A light emitting diode according to claim 16, wherein the first undoped GaN layer has a thickness of about 20 Angstroms to about 30 Angstroms. 
     
     
       19. A light emitting diode according to claim 16, wherein the undoped AlGaN layer has a thickness of about 30 Angstroms to about 50 Angstroms. 
     
     
       20. A light emitting diode according to claim 16, wherein said quantum well comprises a multiple quantum well. 
     
     
       21. A light emitting diode according to claim 16, wherein said quantum well comprises a single quantum well. 
     
     
       22. A pixel that includes a light emitting diode according to claim 16. 
     
     
       23. A display that includes a plurality of pixels according to claim 22.