Photodetector using nanoparticles

Abstract

The present invention relates to a photodetector using nanoparticles, and more particularly, to a novel photodetector wherein surfaces of nanoparticles synthesized by a wet colloidal process are capped with organic materials which then serve as channels for electron migration, or nanoparticles, from which organic materials capped on the surfaces of nanoparticles are removed to form a close-packed particle structure, directly serve to transport electrons. In accordance with specific embodiments of the present invention, it is possible to improve performance of the photodetector and simplify the manufacturing process thereof.

1 . A photodetector, comprising: 
 a substrate;    an insulating layer formed on the substrate; and    two opposite electrodes disposed on the insulating layer, at a predetermined distance,    wherein a nanocrystalline layer, including nanoparticles prepared by a wet colloidal synthesis method and close-packed by removal of a part of or all of surface-capped organic materials, is formed between two opposite electrodes.    
     
     
         2 . The photodetector according to  claim 1 , wherein the nanoparticles are semiconductor nanoparticles selected from the group consisting of HgTe, HgSe, HgS, CdTe, CdSe, CdS, ZnTe, ZnSe, ZnS, PbTe, PbSe, PbS and mixtures thereof.  
     
     
         3 . The photodetector according to  claim 1 , wherein the organic material is selected from the group consisting of alkyldithiol, mercaptoalkyl alcohol, mercaptoalkyl acid, and mixtures thereof.  
     
     
         4 . The photodetector according to  claim 1 , wherein the organic material is selected from the group consisting of 1-thioglycerol, hexanedithiol, octanedithiol, nonanedithiol, dodecanedithiol, mercaptohexanol, mercaptooctanol, mercapto acetic acid, mercapto propionic acid, and mixtures thereof.  
     
     
         5 . The photodetector according to  claim 1 , wherein the nanoparticles have at least one of single structures and core-shell structures.  
     
     
         6 . The photodetector according to  claim 1 , wherein the substrate is selected from the group consisting of silicon, alumina and glass.  
     
     
         7 . The photodetector according to  claim 1 , wherein the insulating film is selected from the group consisting of SiO 2 , A 1   2 O 3 , Indium Tin Oxide and HfO.  
     
     
         8 . The photodetector according to  claim 1 , wherein the electrodes are selected from the group consisting of Au, Al, Pt and Cu.  
     
     
         9 . A photodetector, comprising: 
 a substrate;    an insulating layer formed on the substrate;    two opposite electrodes disposed on the insulating layer, at a predetermined distance; and    a nanocrystalline layer including nanoparticles located between two opposite electrodes, wherein said nanoparticles are uniformly distributed in close proximity to each other and have a uniform size, and wherein the nanocrystalline layer is prepared by a wet colloidal synthesis method and the nanoparticles are close-packed by removal of a part of or all of surface-capped organic materials.    
     
     
         10 . The photodetector according to  claim 9 , further comprising organic material-capped surfaces on the nanoparticles.  
     
     
         11 . A photodetector, comprising: 
 a substrate;    an insulating layer formed on the substrate; and    two opposite electrodes disposed on the insulating layer, at a predetermined distance,    wherein a nanocrystalline layer, including nanoparticles prepared by a wet colloidal synthesis method and close-packed by removal of a part or all of surplus organic material through repetitive washings, is formed between two opposite electrodes.    
     
     
         12 . The photodetector according to  claim 11 , wherein the nanoparticles are semiconductor nanoparticles selected from the group consisting of HgTe, HgSe, HgS, CdTe, CdSe, CdS, ZnTe, ZnSe, ZnS, PbTe, PbSe, PbS and mixtures thereof.  
     
     
         13 . The photodetector according to  claim 11 , wherein the organic material is selected from the group consisting of alkyldithiol, mercaptoalkyl alcohol, mercaptoalkyl acid, and mixtures thereof.  
     
     
         14 . The photodetector according to  claim 11 , wherein the organic material is selected from the group consisting of 1-thioglycerol, hexanedithiol, octanedithiol, nonanedithiol, dodecanedithiol, mercaptohexanol, mercaptooctanol, mercapto acetic acid, mercapto propionic acid, and mixtures thereof.  
     
     
         15 . The photodetector according to  claim 11 , wherein the nanoparticles have at least one of single structures and core-shell structures.  
     
     
         16 . The photodetector according to  claim 11 , wherein the substrate is selected from the group consisting of silicon, alumina and glass.  
     
     
         17 . The photodetector according to  claim 11 , wherein the insulating film is selected from the group consisting of SiO 2 , Al 2 O 3 , Indium Tin Oxide and HfO.  
     
     
         18 . The photodetector according to  claim 11 , wherein the electrodes are selected from the group consisting of Au, Al, Pt and Cu.  
     
     
         19 . A photodetector, comprising: 
 a substrate;    an insulating layer formed on the substrate;    two opposite electrodes disposed on the insulating layer, at a predetermined distance; and    a nanocrystalline layer including nanoparticles located between two opposite electrodes, wherein said nanoparticles are uniformly distributed in close proximity to each other and have a uniform size and wherein the nanocrystalline is prepared by a wet colloidal synthesis method and the nanoparticles are close-packed by removal of a part or all of surplus organic material through repetitive washings.    
     
     
         20 . The photodetector according to  claim 19 , further comprising organic material-capped surfaces on the nanoparticles.