Work Function Control via Nanocrystalline 2D Material Defects
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Solution Overview
Problem
Existing conductive structures fail to effectively control the work function of metals, particularly when using graphene with larger grain sizes, as the work function reduction is not significant when multiple graphene layers are bonded, limiting their applicability in electronic devices.
Innovation Solution
A conductive structure comprising a metal layer bonded with a work function control layer made of a two-dimensional material with defects, such as nanocrystalline graphene, h-BN, or TMD compounds, which can reduce the work function by controlling the grain size and thickness of the two-dimensional material, allowing for effective work function modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If graphene with large grain size is bonded to metal, then the structure is easier to manufacture, but the work function reduction is not significant
Solution Approach 1:
The patent applies parameter changes by controlling the grain size of two-dimensional materials to be 100 nm or less, transforming the physical parameter of the material structure to achieve effective work function control. This resolves the contradiction by changing the grain size parameter from large (easier to manufacture) to small (precise work function control).
Solution Approach 2:
The patent uses composite materials by combining metal layers with two-dimensional materials having specific grain sizes to create a new conductive structure with optimized work function. The composite structure of metal + nanocrystalline two-dimensional material achieves both manufacturability and precise work function control.
2Area of stationary object
If multiple layers of graphene are bonded to metal, then the coverage is improved, but the work function reduction becomes limited
Solution Approach 1:
The patent changes the critical parameter from number of layers to grain size of the two-dimensional material. By controlling grain size to 100 nm or less, even a single layer achieves effective work function control, eliminating the need for multiple layers and resolving the diminishing returns problem.
Solution Approach 2:
The patent applies preliminary action by pre-controlling the grain size of the two-dimensional material during fabrication to 100 nm or less. This preliminary structural control ensures that subsequent bonding to metal layers immediately achieves the desired work function without requiring additional layer stacking.
3Manufacturing precision
If the thickness of work function control layer is increased, then the work function control is enhanced, but the structural stability decreases
Solution Approach 1:
The patent identifies grain size (100 nm or less) as the critical parameter for work function control, replacing thickness as the control variable. This parameter change resolves the contradiction by achieving precise work function control through nanocrystalline structure rather than increased thickness, thereby maintaining structural stability.
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 proposed solution effectively reduces the work function of metals by utilizing two-dimensional materials with defects, achieving a lower work function than the metal layer alone, even with a single layer structure, and maintaining stability within 90% change rate, enhancing the performance of electronic devices.
Implementation Method 1
the work function control layer is configured to control a work function of the conductive structure by being bonded to the conductive material layer
Data Source
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Figure 3~4A
Figure 4B~4D
AI summary
Provided are a conductive structure and a method of controlling a work function of metal. The conductive structure includes a conductive material layer including metal and a work function control layer for controlling a work function of the conductive structure by being bonded to the conductive material layer. The work function control layer includes a two-dimensional material with a defect.