Plasmonic light emitting diode

Abstract

A light emitting diode includes a diode structure containing a quantum well, an enhancement layer, and a barrier layer between the enhancement layer and the quantum well. The enhancement layer supports plasmon oscillations at a frequency that couples to photons produced by combination of electrons and holes in the quantum well. The barrier layer serves to block diffusion between the enhancement layer and the diode structure.

What is claimed is: 
     
         1 . A light emitting diode (LED) comprising:
 a diode structure containing a quantum well;   an enhancement layer that supports plasmon oscillations at a first frequency, wherein the plasmon oscillations having the first frequency couple to photons produced by a combination of electrons and holes in the quantum well; and   a barrier layer and a patterned contact between the enhancement layer and the quantum well, wherein the barrier layer comprises a layer of non-diffusive metal, wherein the barrier layer and the patterned contact block diffusion between the enhancement layer and the diode structure and wherein at least the barrier layer allows the plasmon oscillations of the enhancement layer to interact with the quantum well.   
     
     
         2 . The LED of  claim 1 , wherein the enhancement layer comprises a material selected from the group consisting of silver and gold. 
     
     
         3 . The LED of  claim 1 , wherein the patterned contact is through the barrier layer, the patterned contact being electrically conductive. 
     
     
         4 . The LED of  claim 3 , wherein the patterned contact comprises a metal. 
     
     
         5 . The LED of  claim 1 , wherein the layer of non-diffusive metal is less than 5 nanometers (nm) thick. 
     
     
         6 . The LED of  claim 1 , wherein the non-diffusive metal layer comprises a layer of platinum. 
     
     
         7 . The LED of  claim 6 , wherein the layer of platinum is between about 2 nm and 5 nm thick. 
     
     
         8 . The LED of  claim 1 , wherein the diode structure comprises:
 a p-type structure containing multiple layers having p-type doping;   an intrinsic structure containing multiple layers of undoped material; and   an n-type structure containing multiple layers having n-type doping.   
     
     
         9 . A fabrication method comprising:
 fabricating a diode structure including a quantum well;   depositing a barrier layer and a patterned contact on the diode structure; and   depositing an enhancement layer on the barrier layer and the patterned contact, wherein at least the barrier layer allows plasmon oscillations of the enhancement layer to interact with the quantum well to increase spontaneous emission rates from electron-hole combinations in the quantum well, wherein the barrier layer and the patterned contact block diffusion between the enhancement layer and the diode structure.   
     
     
         10 . The method of  claim 9 , wherein the depositing the barrier layer comprises depositing an insulating material less than about 10 nm thick. 
     
     
         11 . The method of  claim 10 , comprising forming a contact through the barrier layer, the contact making an electrical connection between the enhancement layer and the diode structure. 
     
     
         12 . The method of  claim 9 , wherein the depositing the barrier layer comprises depositing platinum between 2 nm and 5 nm thick. 
     
     
         13 . A light emitting diode (LED) comprising:
 a substrate;   an n-type structure on the substrate;   an intrinsic structure containing a quantum well on the n-type structure;   a p-type structure on the intrinsic structure;   a barrier layer and a patterned contact on the p-type structure; and   an enhancement layer that supports plasmon oscillations at a desired frequency, wherein the barrier layer and the patterned contact block diffusion between the enhancement layer and the p-type structure, wherein the barrier layer allows the plasmon oscillations of the enhancement layer to interact with the quantum well.   
     
     
         14 . The LED of  claim 13 , wherein the substrate comprises gallium arsenide (GaAs). 
     
     
         15 . The LED of  claim 13 , wherein the n-type structure comprises a multi-layer structure that is approximately 20 nanometers thick. 
     
     
         16 . The LED of  claim 13 , wherein the intrinsic structure comprises a multi-layer structure that is approximately 100 nanometers thick. 
     
     
         17 . The LED of  claim 16 , wherein the intrinsic structure produces photons with a desired wavelength of approximately 800 nanometers. 
     
     
         18 . The LED of  claim 13 , wherein the p-type structure comprises a multi-layer structure that is approximately 50 nanometers thick. 
     
     
         19 . The LED of  claim 13 , wherein the enhancement layer comprises a material selected from the group consisting of silver and gold. 
     
     
         20 . The LED of  claim 13 , wherein the patterned contact is through the barrier layer, the patterned contact being electrically conductive.