# US 7,977,761 B2 · Controlled growth of a nanostructure on a substrate, and electron emission devices based on the same

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- Number: US 7,977,761 B2
- Document ID: US7977761B2
- Status: Granted
- Kind: B2
- Application number: 12/725,373
- Filed: 2010-03-16
- Published: 2010-07-08
- Granted: 2011-07-12
- Earliest claimed: 2005-04-25
- Assignees: Smoltek AB
- Inventors: Mohammad Shafiqul Kabir
- Web page: https://patentgrep.com/patent/US7977761B2

## CPC

- C23C 16/04: Coating on selected surface areas, e.g. using masks
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- 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
- C23C 16/26: Deposition of carbon only
- D01F 9/08: of inorganic material (working or processing of metal wire B21F; from softened glass, minerals or slags C03B37/00)
- 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}
- H01J 1/304: Field-emissive cathodes
- H01J 3/022: {with microengineered cathode, e.g. Spindt-type}
- H01J 9/025: {of field emission cathodes}
- H10K 71/12: using liquid deposition, e.g. spin coating
- H10K 85/221: {Carbon nanotubes}
- C01B 2202/34: Length
- C01B 2202/36: Diameter
- H01J 2201/30469: Carbon nanotubes (CNTs)
- H01J 2237/31786: Field-emitting cathode
- H10K 10/462: {Insulated gate field-effect transistors [IGFETs]}
- Y10S 977/813: Of specified inorganic semiconductor composition, e.g. periodic table group IV-VI compositions
- Y10S 977/827: formed from hybrid organic/inorganic semiconductor compositions
- Y10S 977/832: having specified property, e.g. lattice-constant, thermal expansion coefficient
- Y10S 977/932: for electronic or optoelectronic application
- Y10S 977/939: Electron emitter, e.g. spindt emitter tip coated with nanoparticles
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- 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}
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The present invention provides for an array of nanostructures grown on a conducting substrate. The array of nanostructures as provided herein is suitable for manufacturing electronic devices such as an electron beam writer, and a field emission device.

## Claims

### Claim 1

An array of nanostructures supported on a conducting substrate, wherein each nanostructure in the array comprises:
a plurality of intermediate layers between the conducting substrate and the nanostructure, wherein the plurality of intermediate layers include at least one layer that affects a morphology of the nanostructure and at least one layer to affect an electrical property of an interface between the conducting substrate and the nanostructure, wherein at least two of the plurality of intermediate layers are interdiffused, wherein material of the at least two of the plurality of intermediate layers that are interdiffused are present in the nanostructure.

### Claim 2 (depends on 1)

The array of nanostructures of claim 1, wherein at least one of the plurality of intermediate layers is deposited as a continuous film.

### Claim 3 (depends on 1)

The array of nanostructures of claim 1 wherein the conducting substrate comprises a metal.

### Claim 4 (depends on 2)

The array of nanostructures of claim 2 wherein the metal is selected from the group consisting of tungsten, molybdenum, niobium, platinum and palladium.

### Claim 5 (depends on 1)

The array of nanostructures of claim 1 wherein the plurality of intermediate layers comprises a metal layer and a layer of semiconducting material.

### Claim 6 (depends on 4)

The array of nanostructures of claim 4 wherein the layer of semiconducting material is amorphous silicon.

### Claim 7 (depends on 1)

The array of nanostructures of claim 1, wherein the carbon nanostructure is a carbon nanotube.

### Claim 8 (depends on 1)

The array of nanostructures of claim 1, wherein the carbon nanostructure is a carbon nanofiber.

### Claim 9 (depends on 1)

The array of nanostructures of claim 1, wherein the plurality of intermediate layers forms an Ohmic contact.

### Claim 10 (depends on 1)

The array of nanostructures of claim 1, wherein the plurality of intermediate layers forms a Schottky barrier.

### Claim 11 (depends on 2)

The array of nanostructures of claim 2 wherein thickness of the continuous film is between 0.5 nm and 1 μm.

### Claim 12 (depends on 1)

The array of nanostructures of claim 1, wherein the intermediate layer adjacent to the nanostructure is a layer of catalyst, and wherein the catalyst is selected from the group consisting of: Ni, Fe, Mo, NiCr, and Pd.

### Claim 13 (depends on 1)

The array of nanostructures of claim 1, wherein each nanostructure in the array comprises a carbon nanostructure, and wherein each of said carbon nanostructures is spaced apart from any other carbon nanostructure in the array by between 15 nm and 200 nm.

### Claim 14 (depends on 1)

An electron beam writer, comprising:
an array of nanostructures according to claim 1, each nanostructure having a base and a tip, wherein the base is affixed to a first electrode;
a plurality of second electrodes disposed around the nanostructure; and
electrical circuitry that connects the first electrode to the plurality of second electrodes, and is configured to:
cause a voltage difference to arise between the first electrode and the plurality of second electrodes;
cause electrons to be emitted from the tip; and
cause the tip to move in space towards one of the plurality of second electrodes.

### Claim 15 (depends on 1)

A field emission device, comprising:
a plurality of pixels, wherein each pixel comprises:
a conducting substrate;
an array of nanostructures according to claim 1, deposited on the conducting substrate, wherein said plurality of intermediate layers between the nanostructures and the conducting substrate includes at least one layer of semiconducting material;
and wherein the conducting substrate forms an electrode that is in electrical communication with a voltage source and second electrode;
and wherein the second electrode has a coating of phosphor; and
wherein upon application of a voltage between the conducting substrate and the second electrode, the nanostructures emit electrons towards the phosphor coating.