LED Barrier Layer Curvature for Hole Injection
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Solution Overview
Problem
Conventional light emitting devices using group III-V nitride semiconductors face limitations in internal quantum efficiency due to suboptimal interface configurations between active and conductive type semiconductor layers, leading to inefficient hole injection and light emission.
Innovation Solution
A light emitting device design featuring an active layer with uneven surfaces on barrier layers, particularly the uppermost barrier layer, which increases the contact area with the second conductive type semiconductor layer, enhancing hole injection efficiency and light emitting efficiency by increasing the Electron Hole Pair density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat interface is used between the active layer and the second conductive type semiconductor layer, then the device structure is simple, but the contact area is small leading to poor hole injection efficiency
Solution Approach 1:
The patent applies curvature by forming an uneven surface on the barrier layer of the active layer, replacing a flat interface with a curved/rough surface. This increases the contact area between the active layer and the second conductive type semiconductor layer, thereby improving hole injection efficiency without significantly complicating the overall device structure
Solution Approach 2:
The patent applies local quality by creating an uneven surface specifically on the barrier layer that contacts the second conductive type semiconductor layer, while other parts of the device maintain their conventional structure. This localized modification targets the specific area where hole injection occurs, improving efficiency without requiring complex changes throughout the entire device
2Reliability
If the contact area between the active layer and the second conductive type semiconductor layer is increased, then the hole injection efficiency is improved, but the manufacturing precision requirements are increased
Solution Approach 1:
The uneven surface with curved features provides a larger contact area that is more tolerant to manufacturing variations. The curvature distributes the contact points, reducing the precision requirement for each individual contact point while maintaining overall high hole injection efficiency
Solution Approach 2:
The patent changes the surface morphology parameter of the barrier layer from flat to uneven, which fundamentally alters the contact characteristics. This parameter change increases the effective contact area and improves hole injection efficiency while the manufacturing process can achieve this through standard techniques without requiring ultra-precise control
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 design significantly improves internal quantum efficiency and light emitting efficiency by increasing the contact area between the active layer and the second conductive type semiconductor layer, leading to enhanced hole injection and recombination rates.
Implementation Method 1
The LED is a sort of semiconductor device that changes electricity into infrared rays or light by using the characteristics of compound semiconductors
Data Source
AI summary
A light emitting device is provided. The light emitting device includes a first semiconductor layer, an active layer including a plurality of well layers and a plurality of barrier layers on the first semiconductor layer, a second semiconductor layer on the active layer, and an electrode layer on the second semiconductor layer. A top surface of a first barrier layer adjacent to the second semiconductor layer includes an uneven surface and has a larger area than an area of a top surface of a second barrier layer, wherein the first barrier layer has a thickness thicker than a thickness of the second barrier layer.