LED Barrier Layer Sb Regions for Thermal Brightness Stability
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Solution Overview
Problem
The luminous intensity of LEDs decreases with increasing temperature due to material limitations, posing a challenge in maintaining brightness across varying thermal conditions.
Innovation Solution
A light-emitting device with a barrier layer comprising regions of Sb, which raises the conduction band and confines electrons in quantum wells, enhancing the probability of electron-hole combination and maintaining brightness even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional LED materials are used, then the device structure remains simple, but the luminous intensity decreases with increasing temperature
Solution Approach 1:
The barrier layer is divided into three regions with different Sb concentrations: a first region adjacent to the first quantum well, a second region adjacent to the second quantum well, and a third region between them with higher Sb concentration. This local variation in composition creates different conduction band heights in different regions, enabling selective electron confinement at quantum well interfaces while maintaining overall structural simplicity.
Solution Approach 2:
The barrier layer uses a composite material system combining AlGaInP with Sb elements in specific concentrations. The graded Sb composition (1.5×10^18 to 5×10^18 atoms/cm³ in the third region, lower in first and second regions) creates a composite structure that simultaneously achieves electron confinement, reduced temperature coefficient, and maintained luminous intensity across temperature variations.
2Reliability
If the barrier layer uses uniform composition, then the manufacturing process is simple, but electron confinement efficiency decreases
Solution Approach 1:
The barrier layer employs spatially varying Sb concentration with three distinct regions: the third region between quantum wells has higher Sb concentration (1.5×10^18 to 5×10^18 atoms/cm³) to create elevated conduction bands for electron confinement, while the first and second regions adjacent to quantum wells have lower concentrations to maintain proper band alignment and injection efficiency.
Solution Approach 2:
The Sb concentration parameter is systematically varied across the barrier layer thickness to optimize performance. By changing the Sb concentration from the first region through the third region to the second region, the conduction band profile is shaped to achieve effective electron confinement at quantum well interfaces while maintaining overall device reliability.
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 incorporation of Sb in the barrier layer effectively prevents a decrease in brightness with increasing temperature, as evidenced by a lower temperature coefficient, indicating improved thermal stability and luminance retention.
Implementation Method 1
The barrier layer includes a first region adjacent to the first quantum well, a third region adjacent to the second quantum well and a second region disposed between the first region and the second region and comprising Sb
Implementation Method 2
The incorporation of Sb in the barrier layer effectively prevents a decrease in brightness with increasing temperature, as evidenced by a lower temperature coefficient
Implementation Method 3
an active layer formed on the substrate and including a first quantum well, a second quantum well and a barrier layer disposed between the first quantum well and the second quantum well
Data Source
AI summary
A light-emitting device disclosed herein comprises a substrate, an active layer formed on the substrate and including a first quantum well, a second quantum well and a barrier layer disposed between the first quantum well and the second quantum well. The barrier layer includes a first region adjacent to the first quantum well, a third region adjacent to the second quantum well and a second region disposed between the first region and the third region and comprising Sb.