Nanoparticle synthesis
A noble metal nanoparticle can be grown on a semiconductor substrate by contacting a predetermined region of the substrate with a solution including noble metal ions. The predetermined region of the semiconductor substrate can be exposed by applying a polymeric layer over the substrate selectively removing a portion of the polymeric layer. The nanoparticles can be prepared in a predetermined pattern. The nanoparticle can be formed with a barrier separating it from another nanoparticle on the substrate; for example, nanoparticle can be located in a pit etched in the substrate. The size and location of the nanoparticle can be stable at elevated temperatures.
1. A composition comprising:
a noble metal nanoparticle positioned on a predetermined region of a semiconductor substrate, the noble metal nanoparticle being separated from another nanoparticle on the substrate by a barrier, wherein the barrier is a portion of the semiconductor substrate that is raised relative to the region of the semiconductor substrate upon which the nanoparticle is positioned.
2. The composition of claim 1 , wherein the barrier includes a polymeric material.
3. The composition of claim 1 , wherein the barrier is raised relative to the region of the substrate upon which the nanoparticle is positioned.
4. The composition of claim 1 , wherein the substrate is GaAs.
5. The composition of claim 2 , wherein the polymeric material is PMMA.
6. The composition of claim 1 , wherein the nanoparticle is a nanocrystal.
7. The composition of claim 1 , wherein the noble metal is Au.
8. The composition of claim 1 , wherein the nanoparticle has a diameter of 25 nm or smaller, or 10 nm or smaller.
9. A nanomaterial comprising:
a noble metal nanocrystal; and
an amorphous layer comprising an oxide at least partially surrounding the nanoparticle.
10. The nanomaterial of claim 9 , wherein the noble metal is Au.
11. The nanomaterial of claim 9 , wherein the average diameter of the nanocrystal is 25 nm or smaller, or 10 nm or smaller.
12. The nanomaterial of claim 9 , wherein the oxide is derived from the semiconductor material.