Methods of Manufacture for Quantum Dot optoelectronic devices with nanoscale epitaxial lateral overgrowth

Abstract

Optoelectronic devices are provided that incorporate quantum dots as the electroluminescent layer in an inorganic wide-bandgap heterostructure. The quantum dots serve as the optically active component of the device and, in multilayer quantum dot embodiments, facilitate nanoscale epitaxial lateral overgrowth (NELOG) in heterostructures having non-lattice matched substrates. The quantum dots in such devices will be electrically pumped and exhibit electroluminescence, as opposed to being optically pumped and exhibiting photoluminescence. There is no inherent “Stokes loss” in electroluminescence thus the devices of the present invention have potentially higher efficiency than optically pumped quantum dot devices. Devices resulting from the present invention are capable of providing deep green visible light, as well as, any other color in the visible spectrum, including white light by blending different sizes and compositions of the dots and controlling manufacturing processes.

1 - 36 . (canceled) 
     
     
         37 . A method for making a quantum dot optoelectronic device, the method comprising:
 disposing a first layer of a first conductivity type on a substrate;   disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer; and   disposing a second layer of a second conductivity type that is different from the first conductive type on the quantum dot layer and the first layer.   
     
     
         38 . The method of  claim 37 , further comprising disposing an encapsulation layer between the quantum dot layer and the second layer. 
     
     
         39 . The method of  claim 37 , wherein disposing a first layer on the substrate further comprises growing a first layer by metal-oxide chemical vapor deposition (MOCVD). 
     
     
         40 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises disposing a quantum dot layer on only a portion of the first layer such that clusters of quantum dots are disposed on the first layer. 
     
     
         41 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises disposing the quantum dot layer in solution form. 
     
     
         42 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises disposing the quantum dot layer in slurry form. 
     
     
         43 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises chemically attaching the quantum dot layer to the first layer. 
     
     
         44 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises disposing the quantum dot layer in a solid-matrix. 
     
     
         45 . The method of  claim 37 , wherein disposing a quantum dot layer on only a portion of the first layer such that other portions of the first layer remain uncovered by the quantum dot layer further comprises disposing the quantum dot layer in a solid-matrix of porous sol-gel. 
     
     
         46 .- 50 . (canceled) 
     
     
         51 . A method for making a quantum dot optoelectronic device, the method comprising:
 disposing a first layer of a first conductivity type on a substrate;   providing for a plurality of pits in a surface of the first layer;   disposing a plurality of quantum dots on the surface of the first layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer; and   disposing a second layer of a second conductivity type that is different from the first conductivity type on the plurality of quantum dots and the first layer.   
     
     
         52 . The method of  claim 51 , further comprising disposing an encapsulation layer between the plurality of quantum dots and the second layer. 
     
     
         53 . The method of  claim 51 , wherein disposing a first conductive type layer on the substrate further comprises growing a first conductive type layer by metal-oxide chemical vapor deposition (MOCVD). 
     
     
         54 . The method of  claim 51 , wherein providing for a plurality of pits in a surface of the first layer further comprises etching a plurality of pits in a surface of the first layer. 
     
     
         55 . The method of  claim 51 , wherein disposing a plurality of quantum dots on the surface of the first layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer further comprises disposing the plurality of quantum dots in solution form. 
     
     
         56 . The method of  claim 51 , wherein disposing a plurality of quantum dots on the surface of the first type layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer further comprises disposing the plurality of quantum dots in slurry form. 
     
     
         57 . The method of  claim 51 , wherein disposing a plurality of quantum dots on the surface of the first layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer further comprises chemically attaching the plurality of quantum dots to the first layer. 
     
     
         58 . The method of  claim 51 , wherein disposing a plurality of quantum dots on the surface of the first layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer further comprises disposing the plurality of quantum dots in a solid-matrix. 
     
     
         59 . The method of  claim 51 , wherein disposing a plurality of quantum dots on the surface of the first layer such that the quantum dots are generally located proximate the plurality of pits in the surface of the first layer further comprises disposing the plurality of quantum dots in a solid-matrix of pitted sol-gel. 
     
     
         60 .- 63 . (canceled) 
     
     
         64 . The method of  claim 51 , wherein disposing a second layer on the plurality of quantum dots and the first layer further comprises growing a second layer by molecular beam epitaxy. 
     
     
         65 . A method for making a quantum dot optoelectronic device, the method comprising:
 forming a first layer of a first conductivity, an upper surface of the first layer including openings on dislocations in the first layer,   forming a quantum dot layer directly on only a portion of the upper surface of the first layer such that quantum dots are in the openings and that other portions of the upper surface of the first layer remain uncovered by the quantum dot layer, sizes of the openings and the quantum dots being selected such that the openings trap the quantum dots, the dislocations extending down through the first layer below the quantum dots; and   forming a second layer of a second conductivity that is different from the first conductivity directly on the quantum dot layer and on the other portions of the upper surface the first layer.