Photoexcitable material, photochemical electrode, and method for manufacturing photoexcitable material

Abstract

A photoexcitable material includes: a solid solution of MN (where M is at least one of gallium, aluminum and indium) and ZnO, wherein the photoexcitable material includes 30 to 70 mol % ZnO and has a band gap energy of 2.20 eV or less.

What is claimed is: 
     
         1 . A photoexcitable material comprising:
 a solid solution of MN (where M is at least one of gallium, aluminum and indium) and ZnO,   wherein the photoexcitable material includes 30 to 70 mol % ZnO and has a band gap energy of 2.20 eV or less.   
     
     
         2 . The photoexcitable material according to  claim 1 , wherein the photoexcitable material is represented by the following formula:
   M 1.00-x N 1.00-x Zn x O x      where 0.30≦x≦0.70.   
     
     
         3 . The photoexcitable material according to  claim 1 , wherein M is gallium. 
     
     
         4 . The photoexcitable material according to  claim 1 , wherein the photoexcitable is layered. 
     
     
         5 . A photochemical electrode comprising:
 a conductive layer; and   a photoexcitable material provided over the conductive layer and being layered,   wherein the photoexcitable material includes a solid solution of MN (where M is at least one of gallium, aluminum and indium), includes 30 to 70 mol % ZnO and has a band gap energy of 2.20 eV or less.   
     
     
         6 . The photochemical electrode according to  claim 5 , wherein the photoexcitable material is represented by the following formula:
   M 1.00-x N 1.00-x Zn x O x      where 0.30≦x≦0.70.   
     
     
         7 . The photochemical electrode according to  claim 5 , wherein M is gallium. 
     
     
         8 . The photochemical electrode according to  claim 5 , wherein the photoexcitable is layered. 
     
     
         9 . A method for manufacturing a photoexcitable material, comprising:
 preparing an aerosol in which particles of a solid solution of MN (where M is at least one of gallium, aluminum and indium) and ZnO are dispersed in a gas; and   forming a photoexcitable material layer including the particles on a substrate or a conductive layer by ejecting the aerosol from a nozzle onto the substrate or the conductive layer in such a manner the particles collide against a surface of the substrate or the conductive layer.   
     
     
         10 . The method according to  claim 9 , wherein the photoexcitable material contains 30 to 70 mol % ZnO and has a band gap energy of 2.20 eV or less. 
     
     
         11 . The method according to  claim 9 , further comprising annealing the photoexcitable material layer. 
     
     
         12 . The method according to  claim 11 , wherein the annealing comprises annealing the photoexcitable material layer at 600° C. to 850° C. 
     
     
         13 . The method according to  claim 11 , wherein the annealing comprises annealing the photoexcitable material layer in an ammonia atmosphere.