Systems and Methods for Nanowire Growth
The present invention is directed to systems and methods for nanowire growth. In an embodiment, methods for nanowire growth and doping are provided, including methods for epitaxial vertically oriented nanowire growth including providing a substrate material having one or more nucleating particles deposited thereon in a reaction chamber, introducing an etchant gas into the reaction chamber at a first temperature which gas aids in cleaning the surface of the substrate material, contacting the nucleating particles with at least a first precursor gas to initiate nanowire growth, and heating the alloy droplet to a second temperature, whereby nanowires are grown at the site of the nucleating particles. The etchant gas may also be introduced into the reaction chamber during growth of the wires to provide nanowires with low taper.
1 . A population of at least four semiconductor nanowires each having a taper rate along a length of the nanowire of less than about 2 nm/micron.
2 . The population of semiconductor nanowires of claim 1 , wherein the taper rate along the length of each of the nanowires is length than about 1 nm/micron.
3 . The population of semiconductor nanowires of claim 2 , wherein the taper rate along the length of each of the nanowires is length than about 0.5 nm/micron.
4 . The population of semiconductor nanowires of claim 3 , wherein the taper rate along the length of each of the nanowires is length than about 0.3 nm/micron.
5 . The population of semiconductor nanowires of claim 3 , wherein the nanowires comprise silicon.
6 . The population of semiconductor nanowires of claim 3 , wherein the nanowires comprise silicon and germanium.
7 . The population of semiconductor nanowires of claim 5 , wherein the nanowires comprise a core made from silicon and one or more shell layers disposed about the core made from an oxide.