Multiple Quantum Well Light-Emitting Device with Graded Composition
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Solution Overview
Problem
Light-emitting devices with radial-type three-dimensional structures have lower internal quantum efficiency compared to their two-dimensional counterparts, due to non-homogeneous current distribution and reduced light emission.
Innovation Solution
A light-emitting device with a three-dimensional structure featuring semiconductor elements with a shell having multiple quantum wells, where the mass concentration of a third element in the narrow-gap layers increases from the upper to the lower end, improving the internal quantum efficiency by optimizing the current path and light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a radial-type three-dimensional structure is used, then the device complexity is reduced and manufacturing is simplified, but the internal quantum efficiency of the active area decreases
Solution Approach 1:
The patent applies local quality by varying the mass concentration of the third element (e.g., indium) specifically in the narrow-gap layers of the active area. The concentration increases from the upper to lower end of the active area, creating a gradient that optimizes carrier confinement and recombination efficiency locally within the quantum wells, thereby improving internal quantum efficiency without changing the overall three-dimensional radial structure
Solution Approach 2:
The patent changes the compositional parameter of the semiconductor layers by increasing the mass concentration of the third element in the narrow-gap layers from upper to lower end. This parameter variation creates an optimized band structure gradient that enhances carrier confinement and radiative recombination efficiency, resolving the efficiency limitation of radial-type structures
2Reliability
If the mass concentration of the third element is increased in the narrow-gap layers, then the internal quantum efficiency increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent systematically varies the mass concentration of the third element across the active area height, creating a controlled gradient from upper to lower end. This gradual parameter change (increasing concentration) optimizes the band structure for improved carrier confinement and recombination efficiency while maintaining manufacturability through progressive compositional adjustment rather than abrupt changes
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 internal quantum efficiency of the active area is enhanced, potentially exceeding that of two-dimensional structures, with the mass concentration of the third element varying linearly between 0.1% to 9% points, leading to increased light emission.
Implementation Method 1
The active layer may comprise confinement means corresponding to multiple quantum wells. It then comprises an alternation of semiconductor layers of a first material and of semiconductor layers of a second material, each layer of the first semiconductor material being sandwiched between two layers of the second semiconductor material
Implementation Method 2
Light-emitting devices mean devices capable of converting an electric signal into an electromagnetic radiation
Data Source
AI summary
A light-emitting device including a substrate, three-dimensional semiconductor elements resting on the substrate, at least one shell at least partially covering the lateral walls of the semiconductor element, the shell including an active area having multiple quantum wells, and an electrode at least partially covering the shell, at least a portion of the active area being sandwiched between the electrode and the lateral walls of the semiconductor element. The active area includes an alternation of first semiconductor layers mainly including a first element and a second element and of second semiconductor layers mainly including the first element and the second element and further including a third element. In at least three of the layers, the mass concentration of the third element increases in the portion of the active layer as the distance to the substrate decreases.