Charge Doping Control in 2D Heterostructures

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Solution Overview

Problem

Current methods for controlling charge densities in two-dimensional (2D) van der Waals materials lack permanent, large, and uniform local control, particularly in air-sensitive materials and specific layers of heterostructures, limiting applications in photovoltaics and computing.

Innovation Solution

A charge-transfer controlled 2D system is developed, utilizing a 2D active conducting material and a 2D charge transfer source material with overlapping portions, where the 2D active conducting material overlaps the 2D charge transfer source material, including its edge, often with an insulating layer in between, to achieve controlled charge transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If chemical approaches (ionic liquid, polymer electrolyte gating, atomic/molecular intercalation, functionalization, and adsorption) are used to increase charge density in 2D materials, then charge density exceeds 10^14 cm^-2, but sample quality deteriorates significantly

Engineering Contradiction:

Improvecharge densityVSAvoidsample quality

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces an insulating 2D material layer as an intermediary between the charge transfer material and the active conducting material. This intermediary layer enables charge transfer while preserving the quality of the active layer, avoiding direct chemical contact that would degrade sample quality. The insulating layer acts as a mediator that facilitates the desired charge transfer effect without the harmful chemical interactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If chemical approaches are used to control charge density, then charge can be added to 2D materials, but the methods cannot be applied to air sensitive materials nor specific layers of the heterostructure

Engineering Contradiction:

Improveapplicability to air sensitive materials and specific layersVSAvoidcharge density control

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the charge transfer process by using a multi-layer heterostructure where different 2D materials perform specific functions. The charge transfer material is separated from the active conducting material by an insulating layer, allowing independent optimization of each layer. This segmentation enables selective charge transfer to specific layers without affecting other parts of the heterostructure, and protects air-sensitive materials from chemical degradation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs thin 2D film layers that can be precisely controlled in thickness and composition. These thin films enable charge transfer while protecting sensitive materials, as the insulating 2D layer acts as a protective barrier against environmental degradation while still allowing the desired electrical effects to occur.

Inventive Principle:

Principle #30Flexible shells and thin films

3Quantity of substance

If conventional doping methods are used in 2D materials, then charge density can be increased, but permanent, large, and uniform local control is lacking

Engineering Contradiction:

Improvecharge densityVSAvoidlocal control precision

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent implements local quality control by positioning the charge transfer material to overlap with specific regions of the active conducting material. The charge transfer occurs locally where the materials overlap, enabling spatially selective doping with atomically sharp boundaries. This local overlap approach provides precise control over where charge is transferred, allowing different regions of the device to have different charge densities as needed.

Inventive Principle:

Principle #3Local quality

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 precise and permanent control of charge doping in atomically thin materials, creating ultra-sharp p-n junctions and achieving high charge densities, enhancing the performance of 2D devices by allowing for localized and tunable charge modulation without altering the chemical structure of the active layer.

Implementation Method 1

a 2D active conducting material, a 2D charge transfer source material, and at least one overlapping portion wherein the 2D active conducting material overlaps the 2D charge transfer source material

Methodology Applied

Scientific EffectCharge transfer: Conduction (electrical)

Implementation Method 2

the device further comprises an insulating layer such that the at least one overlapping portion comprises the insulating layer disposed between the 2D active conducting material and the 2D charge transfer source material

Methodology Applied

Scientific EffectInsulation: Dielectric

Data Source

PatentUS20230011913A1Method of controlling charge doping in van der waals heterostructures

Publication Date: 2023.01.12 BOSTON COLLEGE

AI summary

The present disclosure is directed to controlling charge transfer in 2D materials. A charge-transfer controlled 2D device comprises a 2D active conducting material, a 2D charge transfer source material, and at least one overlapping portion wherein the 2D active conducting material overlaps the 2D charge transfer source material including at least one edge of the 2D charge transfer source material.