Nitride Semiconductor Light-Emitting Element With Graded Al Composition
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Solution Overview
Problem
Current nitride semiconductor light-emitting elements face challenges in achieving improved characteristics due to heat treatment steps that disrupt the distribution of p-type impurities, leading to inefficiencies in luminous efficiency and energy consumption.
Innovation Solution
A nitride semiconductor light-emitting element is designed with a specific layered structure, including multiple p-type nitride semiconductor layers with controlled Al composition and impurity concentrations, and a multiple quantum well structure, optimized through vapor-phase growth techniques to maintain impurity distribution and enhance luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment steps are performed to improve electrode contact and activate p-type doping, then electrode characteristics and p-type control are improved, but the distribution of p-type impurity becomes disturbed and luminous efficiency deteriorates
Solution Approach 1:
The p-type nitride semiconductor layer is divided into multiple sub-layers with different Al compositions (first sub-layer with higher Al, second sub-layer with lower Al). This segmentation allows the higher Al-content layer to provide better hole injection and electrode contact, while the lower Al-content layer maintains better impurity distribution and reduces thermal damage during heat treatment, thus resolving the contradiction between electrode characteristics and luminous efficiency.
Solution Approach 2:
Different regions of the p-type nitride semiconductor layer are given different Al compositions to optimize local functions. The first sub-layer near the electrode interface has higher Al content for improved contact characteristics, while the second sub-layer has lower Al content to preserve impurity distribution and reduce thermal diffusion effects during heat treatment, thereby balancing electrode performance and luminous efficiency.
2Reliability
If Al composition in p-type nitride semiconductor layer is increased to improve hole injection efficiency, then hole injection efficiency is improved, but band gap increases and luminous efficiency deteriorates
Solution Approach 1:
The p-type nitride semiconductor layer is segmented into sub-layers with graded Al compositions. The first sub-layer has higher Al content (0.05-0.20) to enhance hole injection efficiency at the electrode interface, while the second sub-layer has lower Al content (0.01-0.05) to maintain smaller band gap and better luminous efficiency, thus resolving the contradiction between hole injection and luminous efficiency.
Solution Approach 2:
Different Al compositions are assigned to different sub-layers based on their functional requirements. The first sub-layer near the electrode benefits from higher Al content for improved hole injection, while the second sub-layer maintains lower Al content for optimal light emission efficiency, achieving local optimization of both parameters.
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 solution results in a nitride semiconductor light-emitting element with improved luminous efficiency and electrostatic discharge threshold, effectively addressing the inefficiencies and environmental concerns by maintaining p-type impurity distribution and enhancing hole injection efficiency.
Implementation Method 1
The principle of light emission in the nitride semiconductor light-emitting element resides in recombination of holes and electrons
Implementation Method 2
a first p-type nitride semiconductor layer, a second p-type nitride semiconductor layer and a third p-type nitride semiconductor layer which are different from each other in Al composition and p-type impurity concentration are sequentially vapor-phase-grown on the nitride semiconductor active layer
Data Source
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AI summary
Disclosed is a nitride semiconductor light-emitting element (100) comprising a p-type nitride semiconductor layer 1 (108), a p-type nitride semiconductor layer 2 (109), and a p-type nitride semiconductor layer 3 (110) placed in order above a nitride semiconductor active layer (107), wherein the p-type nitride semiconductor layer 1 (108) and p-type nitride semiconductor layer 2 (109) each contain Al, the average Al composition of the p-type nitride semiconductor layer 1 (108) is equivalent to the average Al composition of the p-type nitride semiconductor layer 2 (109), the p-type nitride semiconductor layer 3 (110) has a smaller band gap than the p-type nitride semiconductor layer 2 (109), the p-type impurity concentration of the p-type nitride semiconductor layer 2 (109) and the p-type impurity concentration of the p-type nitride semiconductor layer 3 (110) are both lower than the p-type impurity concentration of the p-type nitride semiconductor layer 1 (108), and a method for producing same.