Display Light Sources With Quantum Dots

Abstract

A display may be provided with light sources. The light sources may include light emitting diodes. The light sources may have packages formed from package bodies to which the light-emitting diodes are mounted. Layers such as quantum dot layers, light-scattering layers, spacer layers, and diffusion barrier layers may be formed over the package bodies and light-emitting diodes. Quantum dots of different colors may be stacked on top of each other. A getter may be incorporated into one or more of the layers to getter oxygen and water. Quantum dots may be formed from semiconductor layers that are doped with n-type and p-type dopant to adjust the locations of their conduction and valance bands and thereby enhanced quantum dot performance.

What is claimed is: 
     
         1 . A light source, comprising:
 a package body;   a light-emitting diode mounted to the package body; and   quantum dots in the package body that receive light from the light-emitting diodes, wherein a quantum dot of the quantum dots has a semiconductor core and at least one semiconductor shell surrounding the semiconductor core and wherein a selected one of the semiconductor core and the at least one semiconductor shell includes dopant.   
     
     
         2 . The light source defined in  claim 1 , wherein the dopant is an n-type dopant. 
     
     
         3 . The light source defined in  claim 2 , wherein the semiconductor core includes the n-type dopant and wherein the n-type dopant shifts conduction and valence bands of the semiconductor core relative to conduction and valence bands of the at least one semiconductor shell so that the Fermi levels of the semiconductor core and the at least one semiconductor shell are aligned. 
     
     
         4 . The light source defined in  claim 2 , wherein the n-type dopant comprises an n-type dopant selected from the group consisting of: tin (Sn), indium (In), aluminum (Al), chlorine (Cl), bromine (Br), iodine (I), and gallium (Ga). 
     
     
         5 . The light source defined in  claim 1 , wherein the dopant is a p-type dopant. 
     
     
         6 . The light source defined in  claim 5 , wherein the at least one semiconductor shell includes the p-type dopant and wherein the p-type dopant shifts conduction and valence bands of the at least one semiconductor shell relative to conduction and valence bands of the semiconductor core to deepen a quantum well in the quantum dot. 
     
     
         7 . The light source defined in  claim 5 , wherein the p-type dopant comprises a p-type dopant selected from the group consisting of: nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), copper (Cu), lithium (Li), sodium (Na), and silver (Ag). 
     
     
         8 . The light source defined in  claim 1 , wherein the at least one semiconductor shell comprises an outermost semiconductor shell and an intermediate semiconductor shell, wherein the semiconductor core comprises cadmium selenide (CdSe), wherein the intermediate semiconductor shell comprises cadmium sulfide (CdS), and wherein the outermost semiconductor shell comprises zinc sulfide (ZnS). 
     
     
         9 . The light source defined in  claim 8 , wherein the semiconductor core includes the dopant and wherein the dopant is an n-type dopant. 
     
     
         10 . The light source defined in  claim 8 , wherein the outermost semiconductor shell includes a p-type dopant and wherein the intermediate semiconductor shell includes a p-type dopant. 
     
     
         11 . The light source defined in  claim 8 , wherein the intermediate semiconductor shell includes the dopant wherein the dopant is a p-type dopant, and wherein the outermost semiconductor shell and the semiconductor core do not include dopant. 
     
     
         12 . The light source defined in  claim 8 , wherein the intermediate semiconductor shell includes the dopant, wherein the dopant is an n-type dopant, and wherein the outermost semiconductor shell and the semiconductor core do not include dopant. 
     
     
         13 . The light source defined in  claim 1 , wherein the at least one semiconductor shell includes an outermost semiconductor shell and an intermediate semiconductor shell, wherein the outermost semiconductor shell comprises zinc sulfide (ZnS), wherein the intermediate semiconductor shell comprises gallium phosphide (GaP), and wherein the semiconductor core comprises indium phosphide (InP). 
     
     
         14 . The light source defined in  claim 13 , wherein the semiconductor core includes the dopant and wherein the dopant is a p-type dopant. 
     
     
         15 . The light source defined in  claim 13 , wherein the at least one semiconductor shell further comprises an additional intermediate semiconductor shell that is interposed between the outermost semiconductor shell and the intermediate semiconductor shell and wherein the additional intermediate semiconductor shell comprises zinc selenide (ZnSe). 
     
     
         16 . The light source defined in  claim 15 , wherein the intermediate semiconductor shell includes the dopant and wherein the dopant is an n-type dopant. 
     
     
         17 . The light source defined in  claim 1 , wherein the at least one semiconductor shell includes an outermost semiconductor shell and an intermediate semiconductor shell, wherein the outermost semiconductor shell comprises zinc sulfide (ZnS), wherein the intermediate semiconductor shell comprises zinc selenide (ZnSe), and wherein the semiconductor core comprises indium phosphide (InP). 
     
     
         18 . The light source defined in  claim 17 , wherein the intermediate semiconductor shell includes the dopant and wherein the outermost semiconductor shell and the semiconductor core do not include dopant. 
     
     
         19 . A light source, comprising:
 a package body;   a light-emitting diode mounted to the package body; and   quantum dots in the package body that receive light from the light-emitting diodes, wherein at least one quantum dot of the quantum dots comprises:
 a semiconductor core formed from a semiconductor selected from the group consisting of: cadmium selenide (CdSe) and indium phosphide (InP); 
 an outermost semiconductor shell formed from a semiconductor selected from the group consisting of: cadmium sulfide (CdS), zinc selenide (ZnSe), zinc sulfide (ZnS), gallium phosphide (GaP), aluminum phosphide (AlP), manganese sulfide (MnS), and manganese selenide (MnSe): 
 an intermediate semiconductor shell interposed between the semiconductor core and the outermost semiconductor shell, wherein the intermediate semiconductor shell is formed from a semiconductor selected from the group consisting of: cadmium sulfide (CdS), zinc selenide (ZnSe), zinc sulfide (ZnS), gallium phosphide (GaP), aluminum phosphide (AlP), manganese sulfide (MnS), and manganese selenide (MnSe); and 
 a dopant formed in a selected one of the semiconductor core, the outermost semiconductor shell, and the intermediate semiconductor shell, wherein the dopant is a dopant selected from the group consisting of: tin (Sn), indium (In), aluminum (Al), chlorine (Cl), bromine (Br), iodine (I), gallium (Ga), nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), copper (Cu), lithium (Li), sodium (Na), and silver (Ag). 
   
     
     
         20 . The light source defined in  claim 19 , wherein the quantum dot further comprises an additional intermediate semiconductor shell that is interposed between the outermost semiconductor shell and the intermediate semiconductor shell and wherein the additional intermediate semiconductor shell is formed from a semiconductor selected from the group consisting of: cadmium sulfide (CdS), zinc selenide (ZnSe), zinc sulfide (ZnS), gallium phosphide (GaP), aluminum phosphide (AlP), manganese sulfide (MnS), and manganese selenide (MnSe).