Polygonal Rod Light Emitting Element with Segmented Active Layer
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Solution Overview
Problem
Conventional rod-shaped light emitting elements have limited luminous efficiency due to their structure, which restricts their light emitting area and performance.
Innovation Solution
The design incorporates a first conductivity type semiconductor rod with a polygonal column shape, an active layer featuring well layers and ridge portions with a wider bandgap than the well layers, enhancing carrier confinement and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional rod-shaped structure is used, then the light emitting area per unit volume is increased, but the luminous efficiency is not sufficiently high
Solution Approach 1:
The active layer is segmented into multiple quantum well layers separated by barrier layers with wider bandgaps. This segmentation creates discrete regions for carrier confinement and recombination, improving luminous efficiency while maintaining the rod-shaped light emitting structure
Solution Approach 2:
Different regions of the active layer are given different bandgap properties through the use of well layers and barrier layers with varying compositions. The barrier layers have wider bandgaps to confine carriers, while well layers have narrower bandgaps for efficient light emission, creating local quality variations that enhance overall performance
2Reliability
If well layers are disposed over adjacent side surfaces, then carrier confinement is improved, but crystal strain increases
Solution Approach 1:
Ridge portions are introduced as intermediary structures between adjacent well layers on different side surfaces. These ridge portions act as mediators that separate the well layers and provide a transition region, reducing direct interaction between strained layers and thereby decreasing cumulative crystal strain while still maintaining effective carrier confinement
3Area of stationary object
If the active layer covers the entire rod surface, then the light emitting area is maximized, but manufacturing precision becomes difficult to control
Solution Approach 1:
The continuous active layer covering the rod surface is segmented into discrete quantum well layers separated by barrier layers. This segmentation allows for controlled formation of each layer using standard semiconductor fabrication techniques, making it easier to achieve precise thickness and composition control compared to forming a single continuous layer over the entire rod surface
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 significantly improves the luminous efficiency of the rod-shaped light emitting element by increasing light emission recombination frequency and reducing crystal strain, allowing for a wider range of emission wavelengths from red to ultraviolet.
Implementation Method 1
a bandgap of the ridge portion is wider than a bandgap of each of the plurality of well layers
Data Source
AI summary
A light emitting element includes: a substrate; a base layer disposed on the substrate; at least one rod-shaped light emitting portion comprising: a first conductivity type semiconductor rod disposed on the base layer and having a plurality of side surfaces arranged to form a polygonal column shape, an active layer formed of a semiconductor and covering the side surfaces of the first conductivity type semiconductor rod, and a second conductive type semiconductor layer covering the active layer. The active layer includes a plurality of well layers respectively disposed over at least two adjacent side surfaces among the plurality of side surfaces of the first conductivity type semiconductor rod. Adjacent well layers among the plurality of well layers are separated from each other along a ridge line where the at least two adjacent side surfaces are in contact with each other.