Silicon nanoparticle formation by electrodeposition from silicate

Abstract

The invention provides a method for the formation of silicon nanoparticles, in sizes that fluoresce, by electrodeposition of silicon material onto a non-reactive (with HF) metal (e.g., platinum) surface from a solution of silicate and HF or HF/H 2 O 2 . In an embodiment of the invention, a positively biased substrate with a platinum surface is immersed in a solution of sodium metasilicate in HF/H 2 O 2 , a current is drawn and a coating of silicon nanoparticles is formed on the platinum surface.

1 . A method for forming silicon nanoparticles, the method comprising steps of: 
 providing a substrate with a non reactive metal surface;    contacting at least a portion of the non reactive metal surface with an electrodeposition solution including a silicate solution and one of HF/H 2 O 2  and HF; and    positively biasing the substrate with respect to a counter electrode to establish an electrodeposition current to deposit silicon nanoparticles onto the non reactive metal surface.    
   
   
       2 . The method of  claim 1 , wherein the non reactive metal surface comprises a platinum surface.  
   
   
       3 . The method of  claim 2 , wherein the substrate with the platinum surface comprises a semiconductor substrate with a platinum film.  
   
   
       4 . The method of  claim 3 , wherein the semiconductor substrate comprises a silicon wafer.  
   
   
       5 . The method of  claim 4 , further comprising a step of masking the platinum surface to define current paths for selective deposition of the silicon nanoparticles.  
   
   
       6 . The method of  claim 1 , further comprising a step of masking the non reactive metal surface to define current paths for selective deposition of the silicon nanoparticles.  
   
   
       7 . The method of  claim 1 , wherein the substrate comprises a platinum substrate and the non reactive metal surface comprises a surface of the platinum substrate.  
   
   
       8 . The method of  claim 1 , wherein the silicon solution comprises a metasilicate water solution.  
   
   
       9 . The method of  claim 8 , wherein the metasilicate water solution comprises Na 2 SiO 3 .5H 2 O 2 .  
   
   
       10 . The method of  claim 1 , wherein the silicon solution comprises a sodium silicate water solution.  
   
   
       11 . The method of  claim 10 , wherein the sodium silicate water solution comprises sodium oxide and silica.  
   
   
       12 . The method of  claim 10 , wherein the sodium silicate water solution comprises one of Na 4 SiO 4 ; Na 2 SiO 3 ; Na 2 Si 2 O 5 ; Na 2 Si 4 O 9  in water.