Gradient Energy Gap Light-Emitting Device for Lattice Mismatch Reduction
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Solution Overview
Problem
Conventional light-emitting diodes with quantum well structures face limitations in enhancing light efficiency due to lattice mismatch and crystal defects, which affect the performance and longevity of the devices.
Innovation Solution
A light-emitting device with a multi-quantum well structure is designed, featuring a substrate, conductivity semiconductor layers, and a specific gradient energy gap distribution achieved by varying the operational temperature and gas flow rates during the growth of the well and barrier layers, allowing for a controlled indium content and energy gap modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multi-quantum well structure is formed in the active layer to enhance light efficiency, then light emission performance is improved, but lattice mismatch and crystal defects increase
Solution Approach 1:
The patent applies local quality by creating regions with different indium content within the quantum well structure. The well layer has a gradient indium composition where the indium content varies from the first interface to the second interface with the barrier layer, allowing different regions to have optimized properties for light emission while managing lattice mismatch locally.
Solution Approach 2:
The patent changes the indium content parameter continuously across the well layer thickness. By controlling the indium content to decrease from the first interface toward the second interface, the energy gap is modulated to improve light emission efficiency while reducing the accumulation of crystal defects that would occur with uniform high indium content.
2Use of energy by moving object
If indium content is increased in the well regions to enhance light emission, then internal quantum efficiency is improved, but lattice mismatch increases
Solution Approach 1:
The patent implements local quality by creating a non-uniform indium distribution within the well layer. The indium content is highest near the first interface with the first barrier layer and decreases toward the second interface with the second barrier layer, allowing each region to contribute optimally to light emission while managing overall lattice stability.
Solution Approach 2:
The patent uses a composite structure with varying indium gallium nitride compositions. The well layer comprises a gradient of InGaN materials with different indium contents, creating a composite structure that combines the high efficiency benefits of high-indium regions with the structural stability of lower-indium regions, thereby improving internal quantum efficiency while controlling lattice mismatch.
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
This approach results in improved internal quantum efficiency and output power, with increased indium content in the well regions enhancing light emission and reducing lattice mismatch, leading to higher performance compared to conventional light-emitting diodes.
Implementation Method 1
the first energy gap decreases along a stacking direction of the light-emitting device and has a first gradient, the second energy gap increases along the stacking direction and has a second gradient
Implementation Method 2
a well disposed on the first barrier and including a first region having a first energy gap and a second region having a second energy gap and closer to the semiconductor layer than the first region
Implementation Method 3
a light-emitting device with a quantum well structure... improved internal quantum efficiency and output power, with increased indium content in the well regions enhancing light emission
Implementation Method 4
forming a first region by introducing a gallium based gas, an indium based gas, and a nitrogen based gas at a first operational temperature in a first interval; and forming a second region by introducing the gallium based gas, the indium based gas, and the nitrogen based gas at a second operational temperature in a second interval
Data Source
AI summary
A light-emitting device including a substrate; a first conductivity semiconductor layer disposed on the substrate; a first barrier disposed on the first conductivity semiconductor layer; a well disposed on the first barrier and including a first region having a first energy gap and a second region having a second energy gap and closer to the semiconductor layer than the first region; a second barrier disposed on the well; and a second conductivity semiconductor layer disposed on the second barrier; wherein the first energy gap decreases along a stacking direction of the light-emitting device and has a first gradient, the second energy gap increases along the stacking direction and has a second gradient, and an absolute value of the first gradient is smaller than an absolute value of the second gradient.