Nanostructure Semiconductor Light Emitting Device with Multi-Refractive Index Layers
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Solution Overview
Problem
Current semiconductor light emitting devices face challenges in enhancing external quantum efficiency and light extraction efficiency due to limitations in crystallinity and light emission characteristics.
Innovation Solution
A three-dimensional nanostructure semiconductor light emitting device is designed with specific light extraction structures, including light emitting nanostructures, a contact electrode, and a light transmissive protective layer with varying refractive indices, optimizing the arrangement and materials to improve light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional semiconductor light emitting device structure is used, then the device is simple in structure, but the light extraction efficiency is insufficient
Solution Approach 1:
The light transmissive protective layer is divided into multiple portions (first light transmissive portion, second light transmissive portion, and third light transmissive portion) with different refractive indices, each positioned at specific locations to optimize light extraction from different regions of the nanostructures
Solution Approach 2:
Different portions of the light transmissive protective layer are assigned different refractive indices tailored to their specific functions: the first portion (lower refractive index) fills gaps between nanostructures to reduce total internal reflection, while the second and third portions (higher refractive indices) cover the nanostructures to enhance light extraction efficiency at critical locations
2Productivity
If light emitting nanostructures are arranged to emit light through large surface area, then luminous efficiency is improved, but light extraction efficiency requires further improvement
Solution Approach 1:
The refractive index parameter is strategically varied across different portions of the light transmissive protective layer to optimize light extraction: lower refractive index material in the first portion reduces total internal reflection at interfaces, while higher refractive index materials in the second and third portions enhance light coupling and extraction from the nanostructure surfaces
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 significantly enhances light extraction efficiency by reducing lateral light travel and increasing upward light extraction, thereby improving the overall luminous efficiency of the semiconductor light emitting device.
Implementation Method 1
a first light transmissive portion filling space between the plurality of light emitting nanostructures and formed of or including a material having a first refractive index
Implementation Method 2
a second light transmissive portion disposed on an upper surface of the first light transmissive portion to cover the plurality of light emitting nanostructures and formed of or including a material having a second refractive index higher than the first refractive index
Data Source
AI summary
A nanostructure semiconductor light emitting device includes a plurality of light emitting nanostructures, each of which including a nanocore formed of a first conductivity-type semiconductor material, and an active layer and a second conductivity-type semiconductor layer sequentially disposed on a surface of the nanocore, a contact electrode disposed on a surface of the second conductivity-type semiconductor layer and formed of a transparent conductive material, a first light transmissive portion filling space between the plurality of light emitting nanostructures and formed of a material having a first refractive index, and a second light transmissive portion disposed on an upper surface of the first light transmissive portion to cover the plurality of light emitting nanostructures and formed of a material having a second refractive index higher than the first refractive index.