Mid-IR Light-Emitting Element With InGaAs Window Layer
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Solution Overview
Problem
Light-emitting elements with mid-infrared wavelengths face issues of reduced output power due to light absorption within InAs layers and low transmittance at longer wavelengths, and the use of Sb-based materials is costly and prone to voltage breakdown, making them challenging to integrate with typical LED driver circuits.
Innovation Solution
A light-emitting element comprising an n-type semiconductor layer, an InAsSbP active layer, a lattice-matched p-type semiconductor layer, and a lattice-mismatched p-type InGaAs window layer, where the p-type semiconductor layer has a thickness of 20 nm to 520 nm, and the p-type InGaAs window layer is made of InwGa1-wAs with 0≤ w≤0.2, enhancing emission efficiency and output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an InAs layer with lattice-matched composition is formed thick to supply carriers to the active layer, then carrier supply is improved, but light absorption increases and output power is reduced
Solution Approach 1:
The patent changes the composition parameters of the window layer from InAs to InGaAs by adjusting the In composition ratio w (0≤w≤0.2). This parameter change allows the window layer to have both high carrier concentration for supplying carriers to the active layer and appropriate optical properties to reduce light absorption in the mid-infrared region, thereby resolving the contradiction between carrier supply and light transmission.
2Illumination intensity
If Sb-based materials (GaAsSb or AlAsSb) are used for the window layer to achieve proper band gap and lattice matching, then light transmission is improved, but manufacturing cost increases due to expensive Sb
Solution Approach 1:
The patent replaces expensive Sb-based materials with cheaper InGaAs-based materials for the window layer. By using InGaAs with controlled composition (0≤w≤0.2), the patent achieves the required optical and electrical properties without incorporating expensive Sb, thereby significantly reducing material costs while maintaining light transmission performance.
3Use of energy by moving object
If long-wavelength band LEDs containing Sb are used to reduce power consumption, then energy efficiency is improved, but reliability decreases due to breakdown under voltage stress
Solution Approach 1:
The patent replaces Sb-based materials with InGaAs-based materials for the window layer and active layer. This material substitution maintains the long-wavelength emission characteristics (reducing power consumption) while eliminating the voltage breakdown issues associated with Sb-based LEDs, thereby improving reliability without sacrificing energy efficiency.
4Quantity of substance
If a p-type InAs layer is used as the window layer to supply carriers, then carrier concentration is improved, but transmittance at wavelengths of 3500 nm or longer is reduced
Solution Approach 1:
The patent changes the material composition of the window layer from InAs to InGaAs by controlling the In composition ratio w (0≤w≤0.2). This parameter change allows the window layer to maintain high carrier concentration for effective carrier supply while improving transmittance at wavelengths of 3500 nm and longer, thereby resolving the contradiction between carrier supply and optical transmission.
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 configuration improves light emission efficiency and output power by reducing light absorption and increasing transmittance, while avoiding the costs and reliability issues associated with Sb-based materials.
Implementation Method 1
a p-type InGaAs window layer that is lattice-mismatched with the p-type semiconductor layer, on the p-type semiconductor layer, wherein the p-type semiconductor layer has a thickness of 20 nm or more and 520 nm or less
Implementation Method 2
an InAsSbP active layer containing at least In and As on the n-type semiconductor layer
Data Source
AI summary
A light-emitting element having high emission output power and light emission efficiency and a method of manufacturing of the same are provided. A light-emitting element according to the present disclosure includes an n-type semiconductor layer; an InAsSbP active layer containing at least In and As on the n-type semiconductor layer; a p-type semiconductor layer that is lattice-matched with the InAsSbP active layer, on the InAsSbP active layer; and a p-type InGaAs window layer that is lattice-mismatched with the p-type semiconductor layer, on the p-type semiconductor layer, wherein the p-type semiconductor layer has a thickness of 20 nm or more and 520 nm or less.