Photoreactive Sensor with Optical Amplification Phototransistor

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Solution Overview

Problem

Current phototransistors using amorphous silicon or polycrystalline silicon materials face limitations in high-resolution displays due to low mobility and difficulty in achieving large-area coverage, and transition metal chalcogen compounds like MoS2 have low photoreactivity, hindering their application in optical devices.

Innovation Solution

A photoreactive sensor is developed with an optical amplification phototransistor featuring a non-overlapping region between the source and drain electrodes, using a transition metal chalcogen compound channel region and transparent electrodes, to enhance photoconductivity and transparency, and an integrated display panel with a light source for image and photoreactive information generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If transition metal chalcogen compounds (e.g., MoS2) are used as channel material in phototransistors, then mobility is improved, but photoreactivity deteriorates

Engineering Contradiction:

ImprovemobilityVSAvoidphotoreactivity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The channel region is divided into two distinct segments: a first channel region made of transition metal chalcogen compound for high mobility, and a second channel region made of photoreactive semiconductor material for high photoreactivity. This segmentation allows each region to perform its specialized function without compromising the other, resolving the contradiction between mobility and photoreactivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different materials are used in different locations of the channel region. The first channel region uses transition metal chalcogen compound where high mobility is needed, while the second channel region uses photoreactive semiconductor material where light detection is needed. This local differentiation of material properties allows simultaneous optimization of both mobility and photoreactivity.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If amorphous silicon or polycrystalline silicon is used in phototransistors, then manufacturing is easier, but mobility and resolution are limited

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidmobility

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The phototransistor uses a composite channel structure combining transition metal chalcogen compound and photoreactive semiconductor material. This composite approach enables the device to achieve high mobility comparable to crystalline silicon while maintaining compatibility with existing thin-film transistor manufacturing processes, thus improving mobility without sacrificing ease of manufacture.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If flexible substrate is bent, then flexibility is improved, but cracking and opacity increase

Engineering Contradiction:

ImproveflexibilityVSAvoidstructural integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The phototransistor is constructed using thin-film structures that can be deposited on flexible substrates. The thin-film nature of the transistor layers allows the device to bend without cracking, maintaining structural integrity while achieving flexibility. This enables the display to be bent or folded without compromising the reliability of the phototransistor.

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution provides high transparency, mobility, and reliability for transparent electronic devices, improves contact recognition, and reduces power consumption by using the target subject as a power source, enabling efficient sensing and display of fingerprint, contact, and biometric information.

Implementation Method 1

a non-overlapping region which does not overlap with a local gate electrode between a source electrode and a drain electrode is formed, and which senses light for amplifying photoconductivity

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Data Source

PatentUS10890761B2Photoreactive sensor including optical amplification phototransistor, and display panel and vehicle control system including photoreactive sensor

Publication Date: 2021.01.12 UNIVERSITY INDUSTRY COOPERATION GROUP OF KYUNG HEE UNIVERSITY

AI summary

Disclosed is a photoreactive sensor including an optical amplification phototransistor, in which a non-overlapping region that does not overlap with a local gate electrode between a source electrode and a drain electrode is formed and which senses an optical image through the non-overlapping region for amplify photoconductivity; and a contact light emitting device that is formed on the optical amplification phototransistor and generates the optical image corresponding to a contacted surface upon contact with an object.