Cubic Barrier Layer in InGaN Light-Emitting Device
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Solution Overview
Problem
Semiconductor lasers with InGaN layers face reduced luminous efficiency due to current flowing between the InGaN layer and the side surface of the column portion, leading to inefficient light emission.
Innovation Solution
A light-emitting device with a column portion structure that includes a first semiconductor layer, a light-emitting layer with a well and barrier layer, and a barrier layer with a cubic crystal structure, which reduces In incorporation at the column center and enhances light emission efficiency by increasing the diameter of the well layer and reducing strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an InGaN layer is used as the light-emitting layer in a semiconductor laser, then high brightness and narrow emission angle are achieved, but luminous efficiency is reduced due to current flowing between the InGaN layer and the side surface of the column portion
Solution Approach 1:
A cubic crystal structure layer is introduced as an intermediary between the InGaN light-emitting layer and the surrounding structure. This cubic layer acts as a mediator that prevents direct current flow between the InGaN layer and the side surface, thereby reducing energy loss while maintaining the high brightness characteristics of the InGaN material.
Solution Approach 2:
The crystal structure parameter is changed from the conventional hexagonal structure to a cubic crystal structure for the barrier layer. This parameter change fundamentally alters the electrical and optical properties, creating a structure that reduces current leakage and improves luminous efficiency while preserving the high brightness output of the InGaN light-emitting layer.
2Quantity of substance
If In is selectively taken into the center of the column portion during InGaN layer growth, then the light-emitting layer forms, but current flows between the InGaN layer and the side surface, reducing luminous efficiency
Solution Approach 1:
The cubic crystal structure layer is strategically positioned at specific locations (as a barrier layer) within the column portion structure. This creates local quality differentiation where the cubic layer specifically addresses the current leakage problem at the interface between the InGaN layer and side surface, while allowing the InGaN layer to maintain its desired In incorporation and light-emitting properties in other regions.
3Loss of energy
If the well layer diameter is increased to improve light emission, then luminous efficiency improves, but current flow between the well layer and side surface increases
Solution Approach 1:
The cubic crystal structure barrier layer serves as an intermediary that electrically isolates the well layer from the side surface. This mediator allows the well layer diameter to be increased for improved light emission and luminous efficiency, while simultaneously preventing the harmful current flow that would otherwise increase with larger diameter.
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 increases the diameter of the well layer, reduces current flow between the well layer and the side surface, and improves luminance efficiency by confining light effectively within the light-emitting layer, resulting in high luminance and efficient light emission.
Implementation Method 1
the barrier layer includes a first layer provided between the first semiconductor layer and the first well layer, and the first layer has a cubic crystal structure
Data Source
AI summary
A light-emitting device that includes a substrate, and at least one column portion, wherein the column portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and a light-emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is provided between the substrate and the light-emitting layer, the light-emitting layer includes a first well layer, and a barrier layer, the barrier layer includes a first layer provided between the first semiconductor layer and the first well layer, and the first layer has a cubic crystal structure.