Al-containing Layer in Semiconductor Light Emitting Device
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Solution Overview
Problem
Current semiconductor light emitting devices, such as Laser Diodes (LD) and Light Emitting Diodes (LED), face challenges in achieving high luminous efficiency due to electron overflow in active layers, despite various configurations proposed to suppress this issue.
Innovation Solution
A semiconductor light emitting device is designed with specific layer structures, including an n-type semiconductor layer, a p-type semiconductor layer, a first well layer, a first barrier layer, an Al-containing layer, and an intermediate layer, where the Al-containing layer has a band gap energy larger than the barrier layer and a lattice constant smaller than the n-type semiconductor layer, and the intermediate layer has a graded In composition ratio to optimize energy barriers and reduce electron overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional configurations are used to suppress electron overflow in active layers, then some improvement in luminous efficiency is achieved, but there is still room for further improvement
Solution Approach 1:
The active layer is divided into multiple quantum well structures with different band gap energies, creating distinct regions for electron and hole confinement. This segmentation allows better control of carrier distribution and reduces electron overflow while maintaining high recombination efficiency.
Solution Approach 2:
Different regions of the active layer are designed with locally optimized properties - the first quantum well has specific band gap characteristics for electron injection, while the second quantum well has different characteristics for light emission. This local quality optimization enables simultaneous suppression of electron overflow and enhancement of luminous efficiency.
2Reliability
If the band gap energy of the Al-containing layer is increased to suppress electron overflow, then electron confinement improves, but the lattice constant becomes smaller than the n-type semiconductor layer causing potential dislocation issues
Solution Approach 1:
The Al composition ratio in the Al-containing layer is precisely controlled within the range of 0.001 to 0.3, which optimizes the band gap energy for electron confinement while keeping the lattice constant close to that of the n-type semiconductor layer. This parameter optimization resolves the contradiction between electron confinement and lattice stability.
Solution Approach 2:
The Al-containing layer is designed as a composite structure with specific composition Alx1Ga1-x1-y1Iny1N, combining multiple elements to achieve the desired balance between band gap energy and lattice constant. This composite material approach allows simultaneous optimization of electronic properties and structural stability.
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 configuration effectively suppresses electron overflow and enhances hole injection efficiency, leading to improved luminous efficiency and internal quantum efficiency compared to existing devices.
Implementation Method 1
The Al-containing layer has a band gap energy larger than a band gap energy of the first barrier layer
Implementation Method 2
the intermediate layer has a graded In composition ratio to optimize energy barriers and reduce electron overflow
Implementation Method 3
The n-type semiconductor layer includes a nitride semiconductor. The p-type semiconductor layer is provided on a side of <0001> direction of the n-type semiconductor layer and includes a nitride semiconductor
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes an n-type semiconductor layer, a p-type semiconductor layer, a well layer, a barrier layer, an Al-containing layer, and an intermediate layer. The p-type semiconductor layer is provided on a side of [0001] direction of the n-type semiconductor layer. The well layer, the barrier layer, the Al-containing layer and the intermediate layer are disposed between the n-type semiconductor layer and the p-type semiconductor layer subsequently. The Al-containing layer has a larger band gap energy than the barrier layer, a smaller lattice constant than the n-type semiconductor layer, and a composition of Alx1Ga1-x1-y1Iny1N. The intermediate layer has a larger band gap energy than the well layer, and has a first portion and a second portion provided between the first portion and the p-type semiconductor layer. A band gap energy of the first portion is smaller than that of the second portion.