Silicon and silica nanostructures and method of making silicon and silica nanostructures

Abstract

Provided herein are methods for forming one or more silicon nanostructures, such as silicon nanotubes, and a silica-containing glass substrate. As a result of the process used to prepare the silicon nanostructures, the silica-containing glass substrate comprises one or more nanopillars and the one or more silicon nanostructures extend from the nanopillars of the silica-containing glass substrate. The silicon nanostructures include nanotubes and optionally nanowires. A further aspect is a method for preparing silicon nanostructures on a silica-containing glass substrate. The method includes providing one or more metal nanoparticles on a silica-containing glass substrate and then performing reactive ion etching of the silica-containing glass substrate under conditions that are suitable for the formation of one or more silicon nanostructures.

What is claimed is: 
     
         1 . A composition comprising
 one or more silicon nanostructures; and   a silica-containing glass substrate, the silica-containing glass substrate comprising one or more nanopillars;   wherein the silicon nanostructures extend from the nanopillars of the silica-containing glass substrate; and   wherein the silicon nanostructures comprise one or more nanotubes.   
     
     
         2 . The composition of  claim 1 , wherein the silica-containing glass substrate is fused silica glass. 
     
     
         3 . The composition of  claim 1 , wherein the silicon nanostructures have external diameters between about 30 nm and about 200 nm. 
     
     
         4 . The composition of  claim 1 , wherein the silicon nanostructures have lengths between about 50 nm and about 2000 nm. 
     
     
         5 . The composition of  claim 1 , wherein the silicon nanostructures have a surface density on the silica-containing glass substrate of at least 10 10  cm −2 . 
     
     
         6 . The composition of  claim 1 , wherein the silicon nanostructures also comprise nanowires. 
     
     
         7 . A method for preparing the composition of  claim 1 , the method comprising the steps of:
 providing one or more metal nanoparticles on the silica-containing glass substrate; and   performing reactive ion etching of the silica-containing glass substrate under conditions suitable for the formation of the one or more silicon nanostructures.   
     
     
         8 . The method of  claim 7 , wherein the metal nanoparticles are metal dewetted particles. 
     
     
         9 . The method of  claim 7 , wherein the metal nanoparticles have an average lateral cross-section between about 30 nm and about 200 nm. 
     
     
         10 . The method of  claim 7 , wherein the reactive ion etching is performed at a temperature less than 300° C. 
     
     
         11 . The method of  claim 7 , wherein the reactive ion etching is performed at a temperature less than 100° C. 
     
     
         12 . A composition comprising:
 one or more silica nano structures; and   a silica-containing glass substrate, the silica-containing glass substrate comprising one or more nanopillars;   wherein the silica nanostructures extend from the nanopillars of the silica-containing glass substrate; and   wherein the silica nanostructures comprise one or more nanotubes.   
     
     
         13 . The composition of  claim 12 , wherein the silica nanostructures also comprise nanowires. 
     
     
         14 . The composition of  claim 12 , wherein the silica nanostructures are substantially transparent. 
     
     
         15 . The composition of  claim 12 , wherein the silica nanostructures have external diameters between about 30 nm and about 200 nm. 
     
     
         16 . The composition of  claim 12 , wherein the silica nanostructures have lengths between about 50 nm and about 2000 nm. 
     
     
         17 . A method for preparing the composition of  claim 12 , the method comprising the steps of:
 providing one or more metal nanoparticles on a silica-containing glass substrate;   performing reactive ion etching of the silica-containing glass substrate under conditions suitable for the formation of silicon nanostructures comprising silicon nanotubes; and   oxidizing the silicon nanostructures to form the one or more silica nanostructures.   
     
     
         18 . A method for preparing a silica nanotube comprising the steps of:
 providing one or more metal nanoparticles on a silica-containing glass substrate;   performing reactive ion etching of the silica-containing glass substrate under conditions suitable for the formation of a silicon nanotube; and   oxidizing the silicon nanotube to form a silica nanotube.   
     
     
         19 . The method of  claim 18  further comprising the step of removing the silicon nanotube from the silica-containing glass substrate prior to oxidation. 
     
     
         20 . A silica nanotube prepared by the method of  claim 19 .