# US 7,611,740 B2 · Methods for measuring growth rates of carbon nanotubes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,740 B2 - Document ID: US7611740B2 - Status: Granted - Kind: B2 - Application number: 11/404,700 - Filed: 2006-04-14 - Published: 2006-10-26 - Granted: 2009-11-03 - Earliest claimed: 2005-04-21 - Assignees: Tsinghua University; Hon Hai Precision Industry Co., Ltd. - Inventors: Kai-Li Jiang; Kai Liu; Shou-Shan Fan - Web page: https://patentgrep.com/patent/US7611740B2 ## CPC - D01F 9/127: by thermal decomposition of hydrocarbon gases or vapours {or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols} - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - B82Y 40/00: Manufacture or treatment of nanostructures - C01B 32/162: characterised by catalysts - C30B 25/14: Feed and outlet means for the gases; Modifying the flow of the reactive gases - C30B 29/602: {Nanotubes} - C01B 2202/08: Aligned nanotubes - Y10T 428/2931: Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.] - Y10T 436/25875: Gaseous sample or with change of physical state - D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for measuring a growth rate of a carbon nanotube includes the following steps: (a) providing a substrate (12); (b) forming a catalyst layer on the substrate; (c) heating the substrate to a predetermined temperature; (d) intermittently introducing/providing and then interrupting a reaction gas proximate the substrate to grow a patterned carbon nanotube array, each carbon nanotube having at least one line mark formed thereon as a result of the patterned growth; and (e) calculating the growth rate which is equal to a length between a pair of line marks divided by a time interval between said two line marks. ## Claims ### Claim 1 A method for measuring a growth rate of a carbon nanotube, the method comprising the steps of: (a) providing a substrate; (b) forming a catalyst layer on the substrate; (c) heating the substrate to a predetermined temperature; and (d) intermittently introducing a reaction gas proximate the substrate to grow a carbon nanotube array comprised of a plurality of carbon nanotubes each having a plurality of line marks thereon; and (e) calculating the growth rate of at least one carbon nanotube, the growth rate being equal to a length between a pair of line marks divided by a time interval between said two line marks. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the catalyst layer in step (b) is divided into a plurality of portions separated from each other. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein before step (c), the catalyst layer is annealed at an approximate temperature in the range from 200° C. to 400° C. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the heating of step (c) is executed in a reaction furnace, and the temperature therein is approximately in the range from 500° C. to 900° C. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein in step (d), the intermittent introduction of the reaction gas is executed by repeating a process of providing the introduction of the reaction gas for a first predetermined time and interrupting the introduction of the reaction gas for a second predetermined time. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the first predetermined time is approximately in the range from 1 minute to 5 minutes. ### Claim 7 (depends on 5) The method as claimed in claim 5, wherein the second predetermined time is approximately in the range from 10 seconds to 30 seconds. ### Claim 8 (depends on 5) The method as claimed in claim 5, wherein the interrupting process includes introducing a disturbance gas to blow away the reaction gas near the substrate. ### Claim 9 (depends on 8) The method as claimed in claim 8, wherein the disturbance gas is comprised of at least one gas selected from a group consisting of reductive gases and inert gases. ### Claim 10 (depends on 9) The method as claimed in claim 9, wherein the disturbance gas is selected from a group comprised of argon (Ar) gas, nitrogen (N2) gas and hydrogen (H2) gas. ### Claim 11 (depends on 5) The method as claimed in claim 5, wherein the interrupting process includes switching off the introduction of the reaction gas. ### Claim 12 (depends on 11) The method as claimed in claim 11, wherein a disturbance gas is simultaneously introduced to blow off the residual reaction gas near the substrate. ### Claim 13 (depends on 1) The method as claimed in claim 1, wherein the reaction gas in step (c) is a mixture of carbon source gas and protection gas. ### Claim 14 (depends on 13) The method as claimed in claim 13, wherein, when measuring the growth rate of a given carbon nanotube, the first and last segments thereof are neglected.