Nanopillar solar cell using graphene

Abstract

A semiconductor device includes: a conductive layer; a plurality of nanopillars spaced apart from each other overlying the conductive layer, each nanopillar comprising a first semiconductor layer and a second semiconductor layer on the first semiconductor layer, the first semiconductor layer being different in conductivity type from the second semiconductor layer; and a graphene layer overlying the plurality of nanopillars, the graphene layer being connected to each of the plurality of nanopillars.

What is claimed is: 
     
         1 . A semiconductor device, comprising:
 a conductive layer;   a plurality of nanopillars spaced apart from each other overlying the conductive layer, each nanopillar comprising a first semiconductor layer and a second semiconductor layer on the first semiconductor layer, the first semiconductor layer being different in conductivity type from the second semiconductor layer; and   a graphene layer overlying the plurality of nanopillars, the graphene layer being connected to each of the plurality of nanopillars.   
     
     
         2 . The device according to  claim 1 , wherein each nanopillar further includes an aluminum layer on the second semiconductor layer. 
     
     
         3 . The device according to  claim 1 , further comprising:
 a third semiconductor layer on the conductive layer, a material of the third semiconductor layer and a material of the first semiconductor layer are the same;   wherein the plurality of nanopillars are located over the third semiconductor layer.   
     
     
         4 . The device according to  claim 1 , further comprising a substrate, the conductive layer being disposed on the substrate. 
     
     
         5 . The device according to  claim 1 , further comprising:
 a protective layer on the graphene layer.   
     
     
         6 . The device according to  claim 1 , wherein a transverse dimension of the nanopillars is 5-5000 nm. 
     
     
         7 . The device according to  claim 1 , wherein the material of the first semiconductor layer is the same as the material of the second semiconductor layer. 
     
     
         8 . The device according to  claim 1 , wherein a material of the first semiconductor layer is different than a material of the second semiconductor layer. 
     
     
         9 . The device according to  claim 1 , wherein a homogeneous PN junction is formed at an interface between the first semiconductor layer and the second semiconductor layer. 
     
     
         10 . The device according to  claim 2 , wherein the graphene layer is on the aluminum layer.