Nanocrystalline silicon in sio2 composite and freestanding silicon nanoparticles

Abstract

A nanocrystalline-Si/SiO 2 composite containing silicon nanoparticles prepared by curing hydrogen silsesquioxane (HSQ) under reductive thermal conditions in the presence of a gas containing hydrogen is provided. Freestanding photoluminescent silicon nanoparticles are prepared by acid etching the nanocrystalline-Si/SiO 2 composite.

1 . A nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles prepared by curing hydrogen silsesquioxane (HSQ) under reductive thermal conditions in the presence of a gas containing hydrogen. 
     
     
         2 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 1  in the form of a film. 
     
     
         3 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 1  in which said reductive thermal conditions comprise exposing said hydrogen silsesquioxane to a temperature in the range of from about 900° C. to about 1200° C. for about 30 minutes to about two hours. 
     
     
         4 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 3  wherein said reductive thermal conditions include the presence of an inert gas. 
     
     
         5 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 4  wherein said inert gas is nitrogen. 
     
     
         6 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 4  wherein the gas comprises about 2% to about 6% hydrogen and about 94% to about 98% nitrogen. 
     
     
         7 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 2  in which said film is on a substrate. 
     
     
         8 . The nanocrystalline-Si/SiO 2  composite containing silicon nanoparticles as claimed in  claim 7  in which said substrate is optical grade silica. 
     
     
         9 . Freestanding photoluminescent silicon nanoparticles prepared by acid etching the nanocrystalline-Si/SiO 2  composite as claimed in  claim 1 . 
     
     
         10 . Freestanding photoluminescent silicon nanoparticles as claimed in  claim 9  wherein the silicon nanoparticles are exposed to an said acid for about 2 minutes to about 30 minutes and at a temperature in the range of from about 20° C. to about 30° C. 
     
     
         11 . Freestanding photoluminescent silicon nanoparticles as claimed in  claim 9  in which the acid is hydrofluoric acid, nitric acid, or mixtures thereof.