Electromagnetic Wave Detector with Dynamic Fermi Level Control

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Solution Overview

Problem

The existing electromagnetic wave detectors using graphene as a two-dimensional material layer face challenges in varying the Fermi level, leading to inconsistent Schottky barrier formation and reduced detection efficiency.

Innovation Solution

The proposed electromagnetic wave detector includes a semiconductor layer, insulating films, a two-dimensional material layer, electrodes, and a control electrode. This configuration allows for the variation of the Fermi level of the two-dimensional material layer by applying a control voltage, enabling the formation of a Schottky barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two-dimensional material layer (graphene) is used in the electromagnetic wave detector, then the mobility is very high, but the Fermi level cannot be varied from the formation point, leading to inconsistent Schottky barrier formation

Engineering Contradiction:

Improvedetection consistencyVSAvoidFermi level adjustability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a control electrode that can dynamically adjust the Fermi level of the two-dimensional material layer after formation. This transforms the static Fermi level (fixed at formation) into a dynamic parameter that can be tuned according to detection requirements, resolving the contradiction between detection consistency and Fermi level adjustability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the Fermi level parameter of the two-dimensional material layer by applying voltage through the control electrode. This allows the Schottky barrier height to be adjusted according to different detection needs, enabling consistent and reliable detection across various electromagnetic wave energy ranges

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If voltage is applied to the gate electrode and source/drain electrodes to enable OFF operation, then the sensitivity improves, but the detector fails to detect electromagnetic waves when the Schottky barrier is not properly formed

Engineering Contradiction:

Improvedetection sensitivityVSAvoiddetection reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The control electrode provides a feedback mechanism to adjust the Fermi level and Schottky barrier formation based on detection requirements. This ensures that the Schottky barrier is properly formed before high-sensitivity detection mode is activated, maintaining both sensitivity and reliability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary adjustment of the Fermi level through the control electrode before enabling the detection function. This preliminary action ensures that the Schottky barrier is properly formed in advance, preventing detection failures while maintaining high sensitivity

Inventive Principle:

Principle #10Preliminary action

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 ability to vary the Fermi level of the two-dimensional material layer improves the detection sensitivity and stability of the electromagnetic wave detector, allowing it to effectively detect electromagnetic waves across various energy ranges.

Implementation Method 1

an appropriate Schottky barrier is not formed, for example, depending on the deposition condition of the graphene layer

Methodology Applied

Scientific EffectSchottky barrier:

Implementation Method 2

the Fermi level of the graphene layer (two-dimensional material layer) cannot be varied from the Fermi level at the point of time when the graphene layer is formed

Methodology Applied

Scientific EffectFermi level:

Implementation Method 3

The control electrode is connected to the two-dimensional material layer with the second insulating film interposed therebetween

Methodology Applied

Scientific EffectField effect:

Implementation Method 4

voltage is applied to the graphene layer serving as a channel via the source and drain electrodes. As a result, the photo carrier generated in the n-type semiconductor layer is amplified

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS12295176B2Electromagnetic wave detector and electromagnetic wave detector assembly

Publication Date: 2025.05.06 MITSUBISHI ELECTRIC CORP

AI summary

Electromagnetic wave detector includes semiconductor layer, first insulating film, two-dimensional material layer, first electrode, second electrode, second insulating film, and control electrode. First insulating film is arranged on semiconductor layer. First insulating film is provided with opening. Two-dimensional material layer is electrically connected to semiconductor layer in opening. Two-dimensional material layer extends from above opening to first insulating film. Second insulating film is in contact with two-dimensional material layer. Control electrode is connected to two-dimensional material layer with second insulating film interposed therebetween.