1) An array of metal oxide nanoneedles, comprising metal oxide nanoneedles;
wherein one or more of the metal oxide nanoneedles comprise a pointed tip,
5 said pointed tip having a length in the range of about 40 nm to 80 nm and a tip diameter
in the range of about 1 nm to 25 nm.
2) The array of metal oxide nanoneedles as claimed in claim 1, wherein the metal oxide
nanoneedles are vertically aligned on a substrate.
10
3) The array of metal oxide nanoneedles as claimed in claim 1 or claim 2, wherein about
80% to 100% of the metal oxide nanoneedles of the array of metal oxide nanoneedles
comprise a pointed tip, said pointed tip having a length in the range of about 40 nm to
80 nm and a diameter in the range of about 1 nm to 25 nm;
15 or wherein each of the metal oxide nanoneedles of the array of metal oxide
nanoneedles comprise a pointed tip, said pointed tip having a length in the range of
about 40 nm to 80 nm and a tip diameter in the range of about 1 nm to 25 nm.
4) The array of metal oxide nanoneedles as claimed in any of the claims 1 to 3, wherein
20 the metal oxide is selected from the group consisting of zinc oxide (ZnO), preferably
würzite-type zinc oxide (ZnO); titanium oxide (TiO2); tin oxide (SnO2) and silver oxide
(Ag2O).
5) The array of metal oxide nanoneedles as claimed in any of the claims 1 to 4, wherein
25 the nanoneedles are single crystalline.
6) The array of metal oxide nanoneedles as claimed in any of the claims 1 to 5, wherein
the nanoneedles have an entire (total) length in the range of about 1 µm to 20 µm and
a diameter in the range of about 40 nm to 70 nm.
30
7) The array of metal oxide nanoneedles as claimed in any of the claims 1 to 6, wherein
the substrate is an electrically non-conducting material coated with an electrically
conducting material.
38
8) The array of metal oxide nanoneedles as claimed in claim 7, wherein the electrically
non-conducting material is selected from silicon (Si), silicon oxide (SiO2), glass,
ceramic, plastic, and any combination of said materials thereof;
or wherein the electrically conducting material is selected from a metal or metal
5 oxide, electrically conducting polymer, and a combination thereof, wherein the metal
or metal oxide is platinum (Pt), titanium (Ti), chromium (Cr), silver (Ag), gold (Au),
indium tin oxide (ITO), or any combination thereof, and wherein the electrically
conducting polymer is poly(methyl methacrylate).
10 9) The array of metal oxide nanoneedles as claimed in claim 7 or claim 8, wherein the
substrate is:
a) a metal coated substrate comprising a coating of platinum and titanium on
silicon and silicon oxide (Pt/Ti/SiO2/Si), or
15 b) a metal coated substrate comprising a coating of chromium on silicon and
silicon oxide (Cr/SiO2/Si).
10) The array of metal oxide nanoneedles as claimed in any of the claims 1 to 9, wherein
the metal oxide nanoneedles have a c-axis orientation in <002> direction relative to
20 surface of the substrate.