Carbon-Allotrope Active Layer for High-Mobility Thin-Film Transistors

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Solution Overview

Problem

Current thin-film transistors in display devices face challenges with electron mobility, leakage current, and on/off ratio, particularly in active-matrix addressing schemes, where materials like amorphous silicon, oxide semiconductors, and polycrystalline silicon have limitations in terms of performance and cost-effectiveness.

Innovation Solution

An active layer comprising a combination of semiconductor materials and carbon allotropes, such as reduced graphene oxide, unoxidized graphene, graphene nanoribbons, or carbon nanotubes, is used in thin-film transistors to enhance electron mobility and reduce scattering, thereby improving the overall performance of display devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If amorphous silicon is used as the active layer material, then the deposition process is simplified and production cost is reduced, but electron mobility is limited to 0.5 cm²/Vs

Engineering Contradiction:
Improvedeposition process simplicityVSAvoidelectron mobility
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite material consisting of oxide semiconductor and graphene. The oxide semiconductor provides semiconducting properties while graphene enhances electron mobility through its unique two-dimensional structure and high carrier mobility, achieving electron mobility exceeding 10 cm²/Vs while maintaining process simplicity

Inventive Principle:
Principle #40Composite materials

2Reliability

If oxide semiconductor is used as the active layer material, then electron mobility is improved, but leakage current and on/off ratio characteristics deteriorate

Engineering Contradiction:
Improveelectron mobilityVSAvoidleakage current
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The composite structure combines oxide semiconductor with graphene, where the graphene layer provides high electron mobility while the oxide semiconductor maintains proper semiconducting behavior and controls leakage current, achieving both high mobility and low leakage current characteristics

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different materials to different regions of the active layer - oxide semiconductor in regions requiring semiconducting properties and graphene in regions requiring high electron transport, optimizing local characteristics to achieve overall performance improvement

Inventive Principle:
Principle #3Local quality

3Reliability

If polycrystalline silicon is used as the active layer material, then electron mobility is improved, but manufacturing complexity and production cost increase

Engineering Contradiction:
Improveelectron mobilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex polycrystalline silicon processing with a simpler composite approach using oxide semiconductor and graphene, which can be deposited using straightforward techniques while achieving comparable or superior electron mobility characteristics

Inventive Principle:
Principle #40Composite materials

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

The integration of carbon allotropes with semiconductor materials in the active layer significantly improves charge mobility and reduces scattering, leading to better threshold voltage and ON current characteristics, and provides effective semiconducting properties, addressing the limitations of existing materials.

Implementation Method 1

The carbon allotrope is selected from the group consisting of reduced graphene oxide (rGO), unoxidized graphene, graphene nanoribbons, carbon nanotube, and mixtures thereof

Methodology Applied
Scientific EffectGraphene: Graphene

Implementation Method 2

An active layer comprising a combination of semiconductor materials and carbon allotropes, such as reduced graphene oxide, unoxidized graphene, graphene nanoribbons, or carbon nanotubes, is used in thin-film transistors to enhance electron mobility and reduce scattering

Methodology Applied
Scientific EffectElectron mobility enhancement:

Data Source

PatentEP3188252B1Active layer, thin-film transistor comprising the same, and display device comprising the same
Publication Date: 2024.02.14 LG DISPLAY CO LTD
  • EP3188252B1 patent drawingFigure 1~2
  • EP3188252B1 patent drawingFigure 3(a)~4(b)
  • EP3188252B1 patent drawingFigure 5(a)~5(b)

AI summary

Carbon allotropes, a thin-film transistor array substrate comprising the same, and a display device comprising the same are disclosed. The thin-film transistor array substrate comprising a substrate, a gate electrode on the substrate, a gate insulating film on the gate electrode, an active layer positioned on the gate insulating film and comprising a semiconductor material and a plurality of carbon allotropes, and a source electrode and a drain electrode that make contact with the active layer.