Plasmonic Photodiode Using Patterned Metal Electrodes
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Solution Overview
Problem
Current photodiodes are expensive to manufacture due to the need for high-quality semiconductor material, require large quantities of material, and have slow detection speeds due to the thickness of the semiconductor material and the time it takes for electron-hole pairs to reach the electrodes.
Innovation Solution
A photodiode design featuring a thin dielectric layer sandwiched between two metallic plates, with one or both plates patterned in a periodic array to enhance surface plasmon excitation, reducing the thickness of semiconductor material needed and increasing absorption efficiency, allowing for faster operation at lower voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-quality single crystal silicon material is used to ensure flawless crystal structure, then detection precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive single crystal silicon with amorphous silicon, which is a lower-quality, cheaper material. The invention compensates for the material quality deficiency through the plasmonic enhancement structure (metallic plates with periodic patterns) that concentrates light energy to achieve sufficient carrier generation despite the material's imperfections.
Solution Approach 2:
The patent changes the physical state and structure of the semiconductor material from single crystal to amorphous form. This parameter change fundamentally alters the material properties, allowing the use of cheaper materials while maintaining functional performance through the compensating plasmonic structure.
2Measurement precision
If wide semiconductor material is used between metal plates, then light detection efficiency is improved, but the amount of semiconductor material required increases
Solution Approach 1:
The patent introduces periodic patterns (gratings) on the metallic plates that create localized regions of enhanced electromagnetic field intensity. These localized 'hot spots' concentrate the light energy in specific regions of the semiconductor material, creating local quality variations that enhance carrier generation efficiency without requiring increased overall material quantity.
Solution Approach 2:
The patent adds a spatial dimension to the light-matter interaction by introducing periodic structures in the metallic plates. This creates a multi-dimensional field distribution with localized enhancement regions, transforming the uniform illumination into a structured pattern that increases interaction efficiency within the same material volume.
3Measurement precision
If thick semiconductor material is used between electrodes, then photo-absorption is improved, but detection speed decreases
Solution Approach 1:
The patent uses periodic patterns on the metallic plates to create localized regions of intense electromagnetic field within the semiconductor material. These localized field enhancements increase carrier generation rates in specific regions, allowing for faster response times while maintaining adequate overall photo-absorption through the concentrated interaction zones.
Solution Approach 2:
The periodic structures on the metallic plates create resonant electromagnetic fields that oscillate at specific frequencies. This resonant enhancement increases the energy transfer efficiency from light to carriers, improving both absorption efficiency and response speed through the dynamic field interaction.
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
Significantly reduces the amount of semiconductor material required, decreases manufacturing costs, and enhances detection speed while maintaining or improving performance, allowing for efficient detection of specific wavelengths and angles of incident light.
Implementation Method 1
The effect of the pattern is to couple incident light within some range of wavelength and/or incidence angles to surface excitations of the metal surface called surface plasmons, enhancing the field near the surface and resulting in dramatically increased photo-aborption and carrier generation in the dielectric layer.
Data Source
AI summary
Embodiments of the invention provide a method and an apparatus for forming a photodiode. One embodiment provides a thin dielectric layer sandwiched between two metallic plates (electrodes), one or both of which are periodically patterned in one or two dimensions. The effect of the pattern is to couple incident light within some range of wavelength and/or incidence angles to surface excitations of the metal surface called surface plasmons, enhancing the electric field near the surface and resulting in dramatically increased photo-absorption and carrier generation in the dielectric layer.