Nanowire LED Mask Opening Ratio for Reproducible 480 Nm Emission
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Solution Overview
Problem
Existing semiconductor light emitting elements face challenges in achieving high reproducibility for light emission at wavelengths of 480 nm or more, such as blue-green, green, or red, due to limitations in increasing the indium (In) ratio in the active layer.
Innovation Solution
A semiconductor light emitting element is designed with a columnar semiconductor layer comprising an n-type nanowire layer, an active layer on its periphery, and a p-type semiconductor layer, where the opening ratio of the mask is controlled between 0.1% and 5.0% to enhance In incorporation and achieve reliable light emission at desired wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the diameter of the nanowire core is increased to increase the In ratio in the active layer, then the wavelength can be increased, but it is difficult to sufficiently increase the In ratio and achieve high reproducibility for light emission at 480 nm or more
Solution Approach 1:
The invention changes the critical parameter from nanowire core diameter to mask opening ratio. By controlling the mask opening ratio to be 0.1% or more and 5.0% or less, the In ratio in the active layer can be precisely controlled to achieve wavelength of 480 nm or more with high reproducibility. This parameter change enables better control over In incorporation while maintaining manufacturing feasibility.
Solution Approach 2:
The invention performs preliminary action by forming a mask with specifically controlled opening ratio before nanowire growth. This pre-established mask structure determines the In ratio in the subsequent active layer formation, ensuring that the desired wavelength characteristics are achieved from the outset with high reproducibility across multiple devices.
2Manufacturing precision
If the mask opening ratio is decreased to increase In incorporation in the active layer, then the wavelength can be increased to 480 nm or more, but the growth conditions become more difficult to control
Solution Approach 1:
The invention identifies the mask opening ratio as the key parameter to control wavelength, setting it to 0.1% or more and 5.0% or less. This parameter change allows precise wavelength control (480 nm or more) while maintaining ease of manufacture, as the opening ratio can be controlled through standard photolithography processes without requiring complex growth condition adjustments.
3Manufacturing precision
If the nanowire core diameter is increased to improve light emission at longer wavelengths, then the In ratio can be increased, but the crystal quality and external quantum efficiency at high current density deteriorate
Solution Approach 1:
The invention changes the controlling parameter from nanowire core diameter to mask opening ratio. This allows independent optimization: the mask opening ratio controls In composition (and thus wavelength), while the nanowire core diameter can be maintained at optimal values for crystal quality and external quantum efficiency. This decoupling resolves the contradiction between In composition control and device performance.
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 allows for high reproducibility in emitting light at wavelengths of 480 nm or more by optimizing the In ratio in the active layer, improving light emission efficiency and stability.
Implementation Method 1
a columnar semiconductor layer grown from each of openings that are provided in the mask. The columnar semiconductor layer includes an n-type nanowire layer formed at a center thereof, an active layer formed on an outer periphery of the n-type nanowire layer, and a p-type semiconductor layer formed on an outer periphery of the active layer
Data Source
AI summary
A semiconductor light emitting element includes: a growth substrate; a mask formed on the growth substrate; and a columnar semiconductor layer grown from at least one opening that is provided in the mask. The columnar semiconductor layer includes an n-type nanowire layer formed at a center thereof, an active layer formed on an outer periphery of the n-type nanowire layer, and a p-type semiconductor layer formed on an outer periphery of the active layer. An opening ratio of the opening is 0.1% or more and 5.0% or less, and a light emission wavelength is 480 nm or more.