InSb Quantum Dot Film for Infrared Sensitivity and Uniformity
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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 detection, and quantum dots used in photoelectric conversion layers face challenges in achieving high external quantum efficiency and uniformity.
Innovation Solution
A semiconductor film comprising an aggregate of In-containing quantum dots and Group 15 elements, specifically Sb, with a coordinated ligand containing a halogen element, such as bromine, to enhance quantum efficiency and in-plane uniformity, used in photodetection elements and image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon photodiode is used for infrared detection, then the device structure is simple and cost-effective, but the sensitivity in infrared region (wavelength 900 nm or more) is low
Solution Approach 1:
The patent changes the material composition parameters by incorporating In elements and Group 15 elements (Sb, As, or P) in specific ratios into the quantum dot structure. This compositional parameter change enables the quantum dots to detect infrared light with wavelength 900 nm or more, resolving the sensitivity limitation of conventional silicon photodiodes while maintaining manufacturing feasibility through solution-based processing.
Solution Approach 2:
The patent creates composite quantum dot structures combining In elements with Group 15 elements (forming compounds like InSb, InAs, or InP) and integrates them with organic ligands. This composite material approach achieves both high infrared sensitivity and uniformity while avoiding the complexity of epitaxial growth required for traditional InGaAs-based solutions.
2Reliability
If InGaAs-based semiconductor material is used for near-infrared detection, then the quantum efficiency is high, but the manufacturing process requires extremely high-cost processes such as epitaxial growth or substrate sticking
Solution Approach 1:
The patent employs quantum dots that can be synthesized through inexpensive solution-based methods rather than expensive epitaxial growth. The quantum dots are formed using low-cost precursors and processed at lower temperatures, eliminating the need for costly substrate sticking and high-temperature epitaxial equipment, thereby achieving high quantum efficiency at a fraction of the cost.
Solution Approach 2:
The patent replaces the mechanical and thermal processes of epitaxial growth with solution-based chemical synthesis. Instead of using complex epitaxial reactors and high-temperature substrate mounting, the invention uses liquid-phase synthesis methods where quantum dots are formed in solution and then deposited, substituting expensive mechanical systems with simpler chemical processes.
3Reliability
If quantum dots are used for photoelectric conversion layer, then the sensitivity can be improved, but the external quantum efficiency and in-plane uniformity are insufficient
Solution Approach 1:
The patent applies local quality control by specifically optimizing the ligand environment around each quantum dot. The organic ligands are selected and configured to locally passivate surface states and control inter-dot interactions, ensuring uniform optical properties across the entire quantum dot layer. This local optimization of ligand-quantum dot interfaces achieves consistent external quantum efficiency throughout the photoelectric conversion layer.
Solution Approach 2:
The patent systematically adjusts critical parameters including the ratio of In elements to Group 15 elements, the type and concentration of organic ligands, and the synthesis temperature. By precisely controlling these parameters during quantum dot formation, the invention achieves both high sensitivity and uniform external quantum efficiency across the photoelectric conversion layer, overcoming the variability issues of conventional quantum dot approaches.
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, improving infrared sensitivity and reducing noise, making it suitable for advanced photodetection and image sensing applications.
Implementation Method 1
a semiconductor film containing semiconductor quantum dots... photodetection element capable of detecting light in the infrared region... photoelectric conversion layer
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 the ligand includes an inorganic ligand containing a halogen element. There are also provided a photodetection element, an image sensor, a dispersion liquid, and a manufacturing method for a semiconductor film.