Photodetectors Based on Two-Dimensional Quantum Dots

Abstract

A photodetector includes a first electrode; an interlayer disposed on the first electrode; a photoabsorbing layer disposed on the interlayer, the photoabsorbing layer having one or more charge transport materials, and a plurality of two-dimensional quantum dots (2D QDs) dispersed in the one or more charge transport material; and a second electrode disposed on the photoabsorbing layer. A heterostructure photodetector includes a first electrode; a first photoabsorbing layer disposed on the first electrode, the first photoabsorbing layer having a first photoabsorbing material; a second photoabsorbing layer disposed on the first photoabsorbing layer, the second photoabsorbing layer having a second photoabsorbing material; and a second electrode disposed on the second photoabsorbing layer.

What is claimed is: 
     
         1 . A photodetector comprising:
 a first electrode;   an interlayer disposed on the first electrode;   a photoabsorbing layer disposed on the interlayer, the photoabsorbing layer comprising:
 one or more charge transport materials; and 
 a plurality of two-dimensional quantum dots (2D QDs) dispersed in the one or more charge transport material; and 
   a second electrode disposed on the photoabsorbing layer.   
     
     
         2 . The photodetector of  claim 1 , wherein the interlayer has a thickness ranging from about 1 nm to about 1000 nm. 
     
     
         3 . The photodetector of  claim 1 , wherein the photoabsorbing layer comprises from about 10 vol % to about 95 vol % of the 2D QDs. 
     
     
         4 . The photodetector of  claim 1 , wherein the photoabsorbing layer comprises from about 5 vol % to about 90 vol % of the one or more charge transport materials. 
     
     
         6 . The photodetector of  claim 1 , wherein the photoabsorbing layer has a thickness ranging from about 10 nm to about 2 microns. 
     
     
         7 . The photodetector of  claim 1 , wherein the 2D QDs have a thickness of about 1 to about 5 atomic or molecular monolayers and lateral dimensions sufficient to place the 2D QDs in the quantum confinement regime. 
     
     
         8 . A heterostructure photodetector comprising:
 a first electrode;   a first photoabsorbing layer disposed on the first electrode, the first photoabsorbing layer comprising a first photoabsorbing material;   a second photoabsorbing layer disposed on the first photoabsorbing layer, the second photoabsorbing layer comprising a second photoabsorbing material; and   a second electrode disposed on the second photoabsorbing layer.   
     
     
         9 . The heterostructure photodetector of  claim 8 , further comprising an interlayer disposed between the first electrode and the first photoabsorbing layer. 
     
     
         10 . The heterostructure photodetector of  claim 8 , further comprising a transition layer disposed between the first photoabsorbing layer and the second photoabsorbing layer, the transition layer comprising a combination of the first photoabsorbing material and the second photoabsorbing material. 
     
     
         11 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing material is a plurality of two-dimensional quantum dots (2D QDs), a plurality of two dimensional nanosheets (2D nanosheets), or a plurality of convention QDs. 
     
     
         12 . The heterostructure photodetector of  claim 8 , wherein the second photoabsorbing material is a plurality of 2D QDs, a plurality of 2D nanosheets, or a plurality of convention QDs. 
     
     
         13 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing material is a plurality of 2D nanosheets and the second photoabsorbing material is a plurality of 2D QDs. 
     
     
         14 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing material is a plurality of first 2D QDs and the second photoabsorbing material is a plurality of second 2D QDs. 
     
     
         15 . The heterostructure photodetector of  claim 8 , wherein
 the first photoabsorbing material is a plurality of 2D QDs and the second photoabsorbing material is a plurality of conventional QDs, or   the first photoabsorbing material is a plurality of conventional QDs and the second photoabsorbing material is a plurality of 2D QDs.   
     
     
         16 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing material is a plurality of 2D QDs and the second photoabsorbing material is a plurality of 2D nanosheets. 
     
     
         17 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing material has a valence band and a conduction band which is offset from a valence band and a conduction band of the second photoabsorbing material to create a built-in electric field. 
     
     
         18 . The heterostructure photodetector of  claim 8 , wherein the first photoabsorbing layer and the second photoabsorbing layer have a combined thickness ranging from about 50 nm to about 800 nm. 
     
     
         19 . The heterostructure photodetector of  claim 8 , wherein one of the first photoabsorbing layer and the second photoabsorbing layer further comprise a charge transport material. 
     
     
         20 . The heterostructure photodetector of  claim 8 , wherein one of the first photoabsorbing material and the second photoabsorbing material is a plurality of 2D nanosheets, the 2D nanosheets having a thickness between 1 to 10 atomic or molecular monolayers and lateral dimensions extending beyond the quantum confinement regime.