# US 9,520,258 B2 · Selective synthesis of nanotubes without inhibitor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,258 B2 - Document ID: US9520258B2 - Status: Granted - Kind: B2 - Application number: 14/607,533 - Filed: 2015-01-28 - Published: 2016-07-28 - Granted: 2016-12-13 - Earliest claimed: 2015-01-28 - Assignees: Eloret Corporation; Michael Mikio Oye - Applicants: Eloret Corporation - Inventors: Michael Mikio Oye - Web page: https://patentgrep.com/patent/US9520258B2 ## CPC - H01J 9/025: {of field emission cathodes} - H01J 1/304: Field-emissive cathodes - H01J 1/3042: {microengineered, e.g. Spindt-type} - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - B82Y 40/00: Manufacture or treatment of nanostructures - H01J 2201/30469: Carbon nanotubes (CNTs) - Y10S 977/843: Gas phase catalytic growth, i.e. chemical vapor deposition - Y10S 977/939: Electron emitter, e.g. spindt emitter tip coated with nanoparticles - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A method of forming nanotubes may include applying a photoresist to a metal substrate, selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation, removing the second portion of the photoresist from the metal substrate exposing a first portion of the metal substrate, exposing the first portion of the metal substrate to an etchant removing the first portion of the photoresist exposing a second portion of the metal substrate, and growing carbon nanotubes on the second portion of the metal substrate. ## Claims ### Claim 1 A method of forming nanotubes, comprising: applying a photoresist to a metal substrate; selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation; removing the second portion of the photoresist from the metal substrate exposing a first portion of the metal substrate; exposing the first portion of the metal substrate to an etchant; removing the first portion of the photoresist exposing a second portion of the metal substrate; and growing carbon nanotubes on the second portion of the metal substrate. ### Claim 2 (depends on 1) The method of claim 1, wherein the metal substrate comprises nickel, iron, chromium, aluminum, or combinations thereof. ### Claim 3 (depends on 1) The method of claim 1, wherein the electromagnetic radiation is ultraviolet radiation. ### Claim 4 (depends on 1) The method of claim 1, wherein selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation forms a pattern of exposed and unexposed portions of photoresist. ### Claim 5 (depends on 4) The method of claim 4, wherein the pattern of exposed and unexposed photoresist is one of a circular square, triangular, diamond, or alternating concentric rings of first and second portions of the metal substrate according to a plan view of the metal substrate as viewed from the side of the metal substrate on which the carbon nanotubes are grown. ### Claim 6 (depends on 1) The method of claim 1, wherein a nanotube growth inhibitor is not deposited on the metal substrate. ### Claim 7 (depends on 1) The method of claim 1, wherein growing of the carbon nanotubes on the second portion of the metal substrate is done by chemical vapor deposition. ### Claim 8 (depends on 1) The method of claim 1, wherein a mask is used to selectively expose a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation. ### Claim 9 A method of forming an electron source with nanotubes, comprising: depositing a layer of photoresist onto the surface of a metal substrate; applying a mask to the surface of the photoresist and selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation; removing the second portion of the photoresist from the metal substrate exposing a first portion of the metal substrate; exposing the first portion of the metal substrate to an etchant; removing the first portion of the photoresist exposing a second portion of the metal substrate; and growing nanotubes on the second portion of the metal substrate; wherein growing nanotubes on the second portion of the metal substrate further comprises, before growing nanotubes on the second portion of the metal substrate: depositing a subsequent layer photoresist onto the surface of the metal substrate; applying a mask to the surface of the photoresist and selectively exposing a third portion of the photoresist to electromagnetic radiation while not exposing a fourth portion to the electromagnetic radiation; removing the fourth portion of the photoresist from the metal substrate exposing a third portion of the metal substrate; exposing the first portion of the metal substrate to the etchant; removing the third portion of the photoresist exposing a third portion of the metal substrate. ### Claim 10 (depends on 9) The method of claim 9, wherein the metal substrate comprises nickel, iron, chromium, aluminum, or combinations thereof. ### Claim 11 (depends on 9) The method of claim 9, wherein the electromagnetic radiation is ultraviolet radiation. ### Claim 12 (depends on 9) The method of claim 9, wherein selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation forms a pattern of exposed and unexposed portions of photoresist. ### Claim 13 (depends on 12) The method of claim 12, wherein the pattern one of a circular square, triangular, diamond, or alternating concentric rings of first and second portions of the metal substrate according to a plan view of the metal substrate as viewed from the side of the metal substrate on which the carbon nanotubes are grown. ### Claim 14 (depends on 9) The method of claim 9, wherein a nanotube growth inhibitor is not deposited on the metal substrate. ### Claim 15 (depends on 9) The method of claim 9, wherein growing nanotubes on the second portion of the metal substrate further comprises growing nanotubes on the third portion of the metal substrate wherein the density of the nanotubes grown on the second portion of the metal substrate differs from the density of nanotubes grown on the third portion of the metal substrate. ### Claim 16 A system for forming nanotubes, comprising: a photoresist applicator to apply a photoresist to a metal substrate; an electromagnetic radiation source to selectively apply a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation; an etchant applicator to expose a first portion of the metal substrate to an etchant, the first portion of metal substrate being exposed after removing the second portion of the photoresist from the metal substrate; and a carbon nanotube synthesizer to grow carbon nanotubes on the second portion of the metal substrate. ### Claim 17 (depends on 16) The system of claim 16, wherein the metal substrate comprises nickel, iron, chromium, aluminum, or combinations thereof. ### Claim 18 (depends on 16) The system of claim 16, wherein the carbon nanotube synthesizer is a chemical vapor depositor. ### Claim 19 (depends on 16) The system of claim 16, wherein the electromagnetic radiation source selectively exposes a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation to form a pattern of exposed and unexposed portions of photoresist. ### Claim 20 A method of forming nanotubes, comprising: applying a photoresist to a metal substrate; selectively exposing a first portion of the photoresist to electromagnetic radiation while not exposing a second portion to the electromagnetic radiation; removing the second portion of the photoresist from the metal substrate exposing a first portion of the metal substrate; exposing the first portion of the metal substrate to an etchant; removing the first portion of the photoresist exposing a second portion of the metal substrate; and growing carbon nanotubes on the second portion of the metal substrate; wherein a nanotube growth inhibitor is not deposited on the metal substrate.