Dielectric Nanocores Enhance Light Extraction in Nanostructure LEDs
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Solution Overview
Problem
Semiconductor light emitting devices with nanostructures face issues of light absorption between adjacent nanostructures, leading to reduced external light extraction efficiency, and wavelength variations and leakage currents due to differing crystal planes on tips and lateral surfaces.
Innovation Solution
A nanostructure semiconductor light emitting device design featuring a base layer, insulating layers with openings, and dielectric nanocores with a multilayer structure, where the dielectric nanocores have a lower refractive index than the semiconductor layers, enhancing light extraction and reducing leakage currents by altering the optical path and blocking currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple light emitting nanostructures are disposed in a single apparatus, then luminous efficiency is improved due to increased surface area, but light emitted from one nanostructure is absorbed by adjacent nanostructures, reducing external light extraction efficiency
Solution Approach 1:
A dielectric nanocore is introduced as an intermediary structure between adjacent light emitting nanostructures. This nanocore acts as a mediator that redirects light emitted by one nanostructure away from adjacent nanostructures, preventing light absorption losses while maintaining the high surface area configuration for improved luminous efficiency.
Solution Approach 2:
The refractive index parameter of the nanocore is specifically optimized to be lower than that of the surrounding semiconductor layers. This parameter change enables effective light redirection through refraction, allowing the nanocore to function as an optical intermediary that improves external light extraction while preserving the benefits of multiple nanostructures.
2Adaptability or versatility
If the tip of a light emitting nanostructure has a different crystal plane from lateral surfaces, then active layer composition varies, causing wavelength changes, but this also creates thinner semiconductor layers at the tip, increasing leakage current
Solution Approach 1:
The dielectric nanocore serves as a protective intermediary structure that covers the tip region of the light emitting nanostructure. This intermediary layer prevents direct exposure of the thin semiconductor region at the tip, thereby blocking leakage current paths while allowing the wavelength-tuning effect of different crystal planes to be maintained in the active layer.
Solution Approach 2:
The nanocore structure is designed in advance to counteract the harmful effect of leakage current before it can occur. By positioning the insulating nanocore at the tip region where the semiconductor layer is thinnest, the design preemptively blocks potential leakage current paths while preserving the beneficial wavelength variation effect.
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 enhances external light extraction efficiency and reduces wavelength dispersion and leakage currents, improving the overall performance of the semiconductor light emitting device.
Implementation Method 1
the dielectric nanocores have a lower refractive index than the semiconductor layers, enhancing light extraction and reducing leakage currents by altering the optical path
Implementation Method 2
The multilayer structure may be a distributed Bragg reflector (DBR) structure
Data Source
AI summary
There is provided a nanostructure semiconductor light emitting device may including: a base layer formed of a first conductivity-type semiconductor, an insulating layer formed on an upper surface of the base layer and including a first region having a plurality of openings and a plurality of second regions positioned in the plurality of openings and spaced apart from the first region, dielectric nanocores disposed in the plurality of second regions, and a plurality of light emitting nanostructures each including a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer sequentially disposed on the dielectric nanocores.