Quantum Dot Photodiode Wavelength Self-Filtering
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Solution Overview
Problem
Existing near-infrared (NIR) photodiodes, such as indium gallium arsenide (InGaAs) photodiodes, face limitations including the need for external optical filters, high cost, and complex processes, which hinder their adoption in new NIR applications. Additionally, research on internal optical filtering for NIR quantum dot photodiodes is lacking.
Innovation Solution
A wavelength self-filtering ultra-low noise near-infrared quantum dot photodiode manufacturing method is developed, which includes a transparent electrode, a p-type layer acting as an internal optical filter, a quantum dot light absorption layer, an n-type layer, and an upper electrode. The p-type layer is optimized in thickness to reduce noise and function as an internal filter, allowing selective NIR light detection without external filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an InGaAs photodiode is used for NIR detection, then high NIR quantum efficiency is achieved, but external optical filters are required and cost increases
Solution Approach 1:
The patent merges the optical filtering function with the photodiode structure itself by implementing a wavelength self-filtering mechanism within the quantum dot photodiode. This integration eliminates the need for separate external optical filters while maintaining high NIR detection efficiency, directly resolving the contradiction between detection efficiency and device complexity
Solution Approach 2:
The quantum dot photodiode is designed to perform self-filtering of wavelengths through its intrinsic properties. The device serves itself by automatically filtering out unwanted wavelengths and selectively detecting NIR light without requiring external filtering components, thereby reducing device complexity while preserving detection efficiency
2Reliability
If an InGaAs photodiode is used for NIR detection, then high durability is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent changes the material parameters by transitioning from InGaAs to quantum dot materials, which offer similar or superior durability while enabling simpler solution-based manufacturing processes. This parameter change resolves the contradiction between durability and ease of manufacture
Solution Approach 2:
The patent replaces complex vacuum deposition and epitaxial growth processes with solution-based quantum dot deposition methods. This substitution maintains device durability while dramatically simplifying the manufacturing process, addressing the contradiction between reliability and ease of manufacture
3Object-affected harmful factors
If the p-type layer thickness is increased to improve visible light shielding, then internal optical filtering improves, but noise reduction becomes insufficient
Solution Approach 1:
The patent optimizes the p-type layer thickness to a specific parameter range that simultaneously achieves effective visible light shielding and sufficient noise reduction. This precise parameter optimization resolves the contradiction between shielding effectiveness and noise control
Solution Approach 2:
The patent employs multiple p-type layers with optimized thicknesses to create a cumulative filtering effect. By stacking multiple layers, the system achieves both superior visible light blocking and effective noise reduction, resolving the contradiction between these two requirements
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 method achieves selective near-infrared light detection with reduced noise levels, enabling the photodiode to be applicable in various NIR applications while eliminating the need for external optical filters and reducing complexity and cost.
Implementation Method 1
a quantum dot light absorption layer that is formed on the p-type layer to a preset thickness or more to generate excitons through the near-infrared light
Implementation Method 2
a p-type layer that is formed on the transparent electrode to shield the visible light
Data Source
AI summary
The present invention discloses a wavelength self-filtering ultra-low noise near infrared quantum dot photodiode manufacturing method and a near infrared quantum dot photodiode manufactured thereby. According to the present invention, a near infrared (NIR) quantum dot photodiode includes: a transparent electrode through which visible light and near-infrared light pass; a p-type layer that is formed on the transparent electrode to shield the visible light; a quantum dot light absorption layer that is formed on the p-type layer to a preset thickness or more to generate excitons through the near-infrared light; an n-type layer that moves negative charges generated by the excitons; and an upper electrode that is formed on the n-type layer.