Patent ID: 7597941

Claim:
A method of synthesizing and controlling the morphology of tubular nanostructures by controlling the wetting behavior of a low melting metal and a nonreactive substrate in different gas phase growth environments, comprising the steps of: selecting said low melting metal from the group consisting of gallium, indium, and aluminum; selecting said nonreactive substrate from the group consisting of carbon, silicon, graphite, molybdenum, titanium and combinations thereof; depositing said low melting metal in a thin film on said nonreactive substrate; dusting said low melting metal with molybdenum powder to form a prepared substrate; inserting said prepared substrate into a reactor; introducing hydrogen gas into said reactor; subjecting said prepared substrate and said hydrogen gas to means for producing a gas phase excitation, thereby forming a hydrogen plasma at a first selected pressure, at a first selected temperature, and for a first selected period of time, wherein low melting metal droplets are formed on said nonreactive substrate in said hydrogen plasma; injecting at least one feed gas selected from the group consisting of oxygen, methane, nitrogen, hydrogen, and combinations thereof into said reactor in at least one dose for exposing said prepared substrate to said feed gas and said hydrogen plasma at a second selected pressure, at a second selected temperature, and for a second selected period of time for defining a growth stage of a tubular nanostructure, wherein carbon precipitates onto said low melting metal droplets, thereby forming a carbon wall around at least one of said low melting metal droplets, said carbon wall forming and growing tangentially to a surface of said at least one of said low melting metal droplets; controlling the feed gas composition during said growth stage, thereby growing and controlling the morphology of said tubular nano structure; turning off said feed gas and said hydrogen gas; removing said tubular nanostructure from said reactor; and heating said tubular nanostructure to remove said low melting metal therefrom.