Carbon Nanotube Array with Alternating Segments

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for growing carbon nanotubes struggle to achieve high purity semiconducting carbon nanotubes and cannot arbitrarily control chirality or alternate the formation of semiconducting and metallic segments, limiting their application in devices like thin film transistors and photoelectric conversion modules.

Innovation Solution

A method involving the application of electric fields to control the chirality of carbon nanotubes, where a catalyst layer is deposited on a substrate, and by reversing the electric field direction, the proportion of semiconducting carbon nanotube segments can be increased, allowing for the growth of carbon nanotubes with alternating semiconducting and metallic segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional CVD method is used to grow carbon nanotubes, then the growth process is simple and straightforward, but the proportion of semiconducting carbon nanotubes cannot be increased beyond the natural 1:2 ratio with metallic nanotubes

Engineering Contradiction:

Improvepurity of semiconducting carbon nanotubesVSAvoidcomplexity of growth process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The catalyst layer is pre-patterned with specific crystal orientations and compositions before carbon nanotube growth. This preliminary preparation of the catalyst with controlled (100) orientation and iron-nickel composition determines the chirality of growing nanotubes, enabling selective growth of semiconducting nanotubes before the actual growth process begins

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The growth conditions are modified by changing key parameters including catalyst composition (iron-nickel ratio), substrate temperature, and carbon source gas composition. These parameter changes during growth control the chirality distribution, allowing selective production of semiconducting carbon nanotubes with (6,5) or (5,6) chirality

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional methods are used, then the chirality of carbon nanotubes is fixed during growth, but the ability to arbitrarily change chirality or alternate semiconducting and metallic segments is lost

Engineering Contradiction:

Improvecontrol over chiralityVSAvoidease of growth process

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The carbon nanotube growth is conducted in periodic stages with alternating conditions. During odd time periods, conditions favor semiconducting nanotube growth; during even time periods, conditions favor metallic nanotube growth. This periodic modulation of growth parameters creates alternating semiconducting-metallic-semiconducting patterns along the nanotube length

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The growth system transitions from static, fixed-chirality growth to dynamic, controllable-chirality growth. By dynamically adjusting catalyst composition, temperature, and gas flow during growth, the system can switch between producing semiconducting and metallic nanotube segments, enabling arbitrary chirality control

Inventive Principle:

Principle #15Dynamics

3Reliability

If alternating semiconducting and metallic segments are required for devices like thin film transistors, then device performance can be optimized, but conventional methods cannot produce such structured nanotubes

Engineering Contradiction:

Improvedevice performanceVSAvoidstructural control of nanotubes

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The carbon nanotube structure is segmented into distinct semiconducting and metallic sections along its length. Each segment is grown under specific conditions that determine its electrical properties, creating a multi-functional nanotube structure where different segments serve different functional roles in devices like thin film transistors and photoelectric conversion modules

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the production of carbon nanotubes with controlled chirality and alternating semiconducting and metallic segments, enhancing their suitability for applications in thin film transistors, light detectors, and photoelectric conversion devices by improving their electrical properties and integration.

Implementation Method 1

Methodology Applied

Scientific EffectElectric field effect: Electric Field

Implementation Method 2

depositing a catalyst layer on a substrate; heating the reaction chamber to a predetermined temperature; introducing a carbon source gas and a protective gas to grow a first carbon nanotube structure

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS10418557B2Carbon nanotube array

Publication Date: 2019.09.17 HON HAI PRECISION INDUSTRY CO LTD

AI summary

A carbon nanotube array with equal or other ratio of semiconductive to conductive elements in integrated form including: a plurality of carbon nanotubes arranged in an array, wherein each carbon nanotube includes a semiconducting carbon nanotube segment and a metallic carbon nanotube segment, and the semiconducting carbon nanotube segment and the metallic carbon nanotube segment are connected with each other.