QD–TMD Heterojunction Synaptic Device for Infrared Recognition

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Solution Overview

Problem

Existing optoelectronic devices struggle to accurately and quickly recognize objects using infrared wavelengths due to interference from visible light, necessitating improved photodetection devices with high sensitivity and rapid response to infrared signals for safe and efficient autonomous driving.

Innovation Solution

An optoelectronic synaptic device with a photoactive layer comprising a heterojunction of inorganic quantum dots and a two-dimensional semiconductor material, specifically InAs quantum dots and transition metal dichalcogenides like WSe2, forming a vertical heterojunction structure to enhance learning and forgetting characteristics through reversible charge trapping and de-trapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If LiDAR based on InGaAs is used for 900 nm band detection, then infrared photodetection capability is improved, but recognition rate is lowered when optical signals overlap with visible light

Engineering Contradiction:

Improveinfrared photodetection accuracyVSAvoidobject recognition rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by creating a heterojunction structure where different materials (quantum dots and transition metal dichalcogenide) are combined to achieve different functional properties in specific regions. The quantum dots provide infrared sensitivity while the TMD layer provides visible light filtering, allowing the device to simultaneously achieve infrared detection capability and visible light rejection without compromising overall recognition accuracy.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If photodetection devices are made more sensitive to infrared wavelengths, then object recognition accuracy is improved, but device complexity increases

Engineering Contradiction:

Improveinfrared signal detection sensitivityVSAvoidphotodetector structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs composite materials by combining quantum dots with transition metal dichalcogenide in a heterojunction structure. This composite approach enables the device to achieve high infrared sensitivity through the quantum dots while the TMD component provides structural stability and additional functional benefits, thereby achieving enhanced performance without proportionally increasing device complexity.

Inventive Principle:

Principle #40Composite materials

3Productivity

If autonomous driving processes are performed in a single device to improve efficiency, then processing speed is improved, but device functionality requirements increase

Engineering Contradiction:

Improveinformation processing speedVSAvoiddevice functional requirements

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements universality by designing the optoelectronic synaptic device to perform multiple functions within a single integrated structure. The device simultaneously provides photodetection, synaptic computation, and neuromorphic processing capabilities through its heterojunction architecture, enabling it to handle various stages of autonomous driving processing (sensing, recognition, decision-making) without requiring separate specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 device achieves high sensitivity and rapid response to near-infrared wavelengths, enabling accurate object recognition and neuromorphic characteristics for efficient, low-power, and high-speed information processing, mimicking human visual-brain functions.

Implementation Method 1

an optoelectronic synaptic device comprising: a photoactive layer provided on a substrate and including inorganic quantum dots and a two-dimensional semiconductor material

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

forming a vertical heterojunction structure to enhance learning and forgetting characteristics through reversible charge trapping and de-trapping

Methodology Applied

Scientific EffectCharge trapping:

Data Source

PatentEP4550986B1Optoelectronic synaptic device provided with photoactive layer including heterojunction of quantum dots(QD) and transition metal dichalcogenide(TMD)

Publication Date: 2025.10.22 INDUSTRYACADEMIC COOPERATION FOUNDATION GYEONGSANG NATIONAL UNIVERSITY

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Figure 3(a)~3(d)
Figure 4(a)~4(f)

AI summary

As the optoelectronic synaptic device according to a preferred embodiment of the present invention includes a photoactive layer in which a heterojunction is formed as inorganic quantum dots that accept a near-infrared light signal directly contacts a transition metal dichalcogenide as a two-dimensional semiconductor material that exhibits synaptic characteristics, there is an effect of making a synaptic response to an optical signal in the near-infrared wavelength range. Therefore, as a function of simulating the human visual-brain function, which shows the neuromorphic characteristics by the photo response (visual response) of the infrared wavelength, together with light detection characteristics sensitively and rapidly responding to an infrared wavelength signal as well as a visible light signal, can be implemented in a single device for the sake of accurate recognition of objects, it can be easily applied in the autonomous driving mobility field.