Core-Multishell Nanowire Light Emitting Element
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Solution Overview
Problem
Conventional semiconductor light emitting elements with planar p-n junctions face challenges in achieving both high luminescence and low power consumption simultaneously due to increased power consumption and self-absorption with larger junction areas, and reduced luminescence with lower current injection.
Innovation Solution
The development of a light emitting element using core-multishell nanowires formed on a group IV semiconductor substrate with a (111) surface, where the nanowires have a core-multishell structure and side surfaces covered with a metal electrode, allowing for efficient light emission and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the area of the p-n junction is increased to increase luminescence, then luminescence is improved, but power consumption and self-absorption are increased reducing effective luminous efficiency
Solution Approach 1:
The patent transitions from a planar p-n junction (2D) to a three-dimensional nanowire structure with radial p-n junctions. This dimensional change allows light to be emitted primarily from the top surface while the p-n junction occurs radially around the nanowire core, separating the light emission path from the carrier recombination region and reducing self-absorption losses.
Solution Approach 2:
The patent divides the light emitting element into multiple vertical nanowire segments, each with its own radial p-n junction. This segmentation allows for increased total luminescence area without proportionally increasing power consumption, as each nanowire segment operates independently with efficient carrier injection and light extraction.
2Loss of energy
If the injection rate for current is reduced to reduce power consumption, then power consumption is reduced, but luminescence is lowered
Solution Approach 1:
The patent creates localized p-n junctions at the radial interface of each nanowire, concentrating carrier recombination and light emission in specific regions. This local quality enhancement allows for efficient luminescence generation with lower overall current injection rates, as each localized junction operates at optimal efficiency.
3Illumination intensity
If multiple nanowires are arranged at high density to increase luminescence, then luminescence is improved, but manufacturing precision and arrangement control become more difficult
Solution Approach 1:
The patent employs self-organized nanowire growth processes where nanowires automatically arrange themselves in dense, ordered patterns during fabrication. This self-service mechanism eliminates the need for complex external alignment procedures, enabling high-density nanowire arrangements with excellent manufacturing precision through inherent physical self-organization.
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 approach enables high luminescence with low power consumption by increasing the emission area and reducing self-absorption, while allowing for high-density nanowire arrangement and efficient current injection.
Implementation Method 1
A semiconductor light emitting element, such as a light emitting diode or a semiconductor laser, has a general structure wherein an n-type semiconductor and a p-type semiconductor are junctioned together on a semiconductor substrate. Such a light emitting element emits light by employing a radiative recombination of electron-hole pairs, which occurs at a p-n junction.
Implementation Method 2
Since a semiconductor nanowire has a large ratio of height to diameter, the semiconductor nanowire is characterized in that self-absorption is low, and most of the light that is generated can easily be emitted outside.
Implementation Method 3
since a semiconductor nanowire has a very small diameter (width), only low-current injection is required for obtaining a radiative recombination of electron-hole pairs.
Data Source
AI summary
Disclosed is a light emitting element, which emits light with small power consumption and high luminance. The light emitting element has: a IV semiconductor substrate; two or more core multi-shell nanowires disposed on the IV semiconductor substrate; a first electrode connected to the IV semiconductor substrate; and a second electrode, which covers the side surfaces of the core multi-shell nanowires, and which is connected to the side surfaces of the core multi-shell nanowires. Each of the core multi-shell nanowires has: a center nanowire composed of a first conductivity type III-V compound semiconductor; a first barrier layer composed of the first conductivity type III-V compound semiconductor; a quantum well layer composed of a III-V compound semiconductor; a second barrier layer composed of a second conductivity type III-V compound semiconductor; and a capping layer composed of a second conductivity type III-V compound semiconductor.