InSb Quantum Dot Semiconductor Film for Infrared Detection
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Solution Overview
Problem
Current photodetection elements, such as silicon photodiodes and InGaAs-based materials, have limitations in sensitivity and cost-effectiveness for infrared light detection, and quantum dots like PbS require complex processes, while existing semiconductor quantum dots with In and Group 15 elements do not fully meet the requirements for high external quantum efficiency and uniformity.
Innovation Solution
A semiconductor film comprising an aggregate of quantum dots with an In element and a Group 15 element, specifically Sb, where the In to Sb ratio is 1.1 or more, and a ligand coordinated to the quantum dots, including inorganic ligands, is used to enhance external quantum efficiency and in-plane uniformity, suitable for photodetection elements and image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon photodiode is used for photodetection, then the structure is simple and cost is low, but sensitivity in infrared region (900 nm or more) is low
Solution Approach 1:
The patent changes the material composition parameter by using In-rich InSb quantum dots with specific In/Sb ratio (1.1 or more), which modifies the band gap and optical absorption characteristics to enable high sensitivity in the infrared region while maintaining cost-effectiveness
Solution Approach 2:
The patent employs composite material structure by combining InSb quantum dots with specific ligands (including inorganic ligands) to create a photoelectric conversion layer that achieves both high infrared sensitivity and good in-plane uniformity
2Reliability
If InGaAs-based semiconductor material is used for near-infrared detection, then sensitivity in infrared region is improved, but manufacturing cost becomes extremely high due to epitaxial growth and substrate sticking processes
Solution Approach 1:
The patent uses colloidal quantum dots that can be manufactured through simple one-pot synthesis methods at low cost, replacing expensive epitaxial growth processes. The quantum dots are produced as disposable nanoparticles that can be easily deposited on substrates without requiring complex equipment
Solution Approach 2:
The patent replaces complex mechanical manufacturing processes (epitaxial growth, substrate sticking) with chemical synthesis methods to produce quantum dots, significantly simplifying the manufacturing process and reducing costs while maintaining infrared detection performance
3Reliability
If PbS quantum dot is used for photoelectric conversion layer, then infrared detection is possible, but the manufacturing process becomes complex
Solution Approach 1:
The patent changes the composition parameter by using In-rich InSb quantum dots with controlled In/Sb ratio, which simplifies the synthesis process compared to PbS quantum dots while maintaining infrared detection capability
Solution Approach 2:
The patent employs InSb quantum dots that can be synthesized through simple one-pot methods at lower cost and complexity compared to PbS quantum dots, providing an alternative material that is easier to manufacture
4Measurement precision
If external quantum efficiency is increased for better light detection accuracy, then detection accuracy improves, but in-plane variation in external quantum efficiency increases causing noise
Solution Approach 1:
The patent optimizes the composition parameter by controlling the In/Sb ratio to be 1.1 or more, which simultaneously improves external quantum efficiency and suppresses in-plane variation, achieving both high detection accuracy and uniformity
Solution Approach 2:
The patent ensures uniform distribution of InSb quantum dots throughout the photoelectric conversion layer, creating consistent local properties across the entire layer to minimize in-plane variation and reduce noise
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 semiconductor film achieves high external quantum efficiency and excellent in-plane uniformity, particularly for infrared light detection, leading to improved accuracy and reduced noise in photodetection elements and image sensors.
Implementation Method 1
a silicon photodiode in which a silicon wafer is used as a material of a photoelectric conversion layer has been used in a photodetection element
Implementation Method 2
a ligand that is coordinated to the semiconductor quantum dot
Data Source
AI summary
There is provided a semiconductor film containing an aggregate of semiconductor quantum dots that contain an In element and a Group 15 element and a ligand that is coordinated to the semiconductor quantum dot, in which the Group 15 element includes an Sb element, and a ratio of the number of the In elements to the number of the Group 15 elements in the semiconductor quantum dot is 1.1 or more. There are also provided a photodetection element, an image sensor, and a manufacturing method for a semiconductor quantum dot.