LED Nanowire Upper-Section Homogenization for Wavelength Control
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Solution Overview
Problem
Existing optoelectronic devices with axial-type light-emitting diodes face challenges in precisely controlling the average diameter of three-dimensional semiconductor elements, leading to uncontrolled wavelength dispersion of the radiation emitted.
Innovation Solution
The method involves forming three-dimensional semiconductor elements with a lower portion and an upper portion, where the upper portion is formed by molecular beam epitaxy (MBE) at a pressure of less than 1.33 mPa, resulting in a flared structure with a cross-sectional area greater than 20% of the lower portion, and a III/V ratio between 1.3 and 2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal-organic chemical vapor deposition (MOCVD) is used to form three-dimensional semiconductor elements, then the manufacturing process is simple and efficient, but the average diameter of the semiconductor elements cannot be precisely controlled, leading to uncontrolled wavelength dispersion
Solution Approach 1:
The semiconductor element formation process is divided into two distinct stages: first, MOCVD is used to form the lower portion of the semiconductor element quickly and efficiently; second, molecular beam epitaxy (MBE) is used to form the upper portion with precise diameter control. This segmentation allows each process to optimize for its specific function, resolving the contradiction between manufacturing efficiency and precision control.
Solution Approach 2:
The invention changes the deposition pressure parameter from typical MOCVD conditions (higher pressure) to ultra-high vacuum conditions in MBE (less than 1.33×10^-3 Pa). This parameter change enables precise control of the upper portion diameter while maintaining the efficiency benefits of MOCVD for the lower portion formation.
2Adaptability or versatility
If the average diameter of semiconductor elements varies, then the manufacturing process is more flexible and adaptable, but the wavelength of emitted radiation becomes uncontrolled and dispersed
Solution Approach 1:
The invention applies different quality requirements to different parts of the semiconductor element: the lower portion can have varied dimensions to accommodate manufacturing flexibility, while the upper portion is specifically engineered with controlled diameter and flared geometry to ensure consistent wavelength emission. This local differentiation resolves the contradiction between overall manufacturing adaptability and specific wavelength precision.
3Manufacturing precision
If molecular beam epitaxy is used to form the upper portion at ultra-high vacuum pressure, then the diameter control precision is improved, but the device complexity increases
Solution Approach 1:
The invention segments the formation process into two distinct phases using two different deposition techniques. The first phase (MOCVD) handles the bulk formation efficiently, while the second phase (MBE) provides the precision finishing on the upper portion. This segmentation justifies the increased complexity by delivering precise diameter control that cannot be achieved with a single process.
Solution Approach 2:
The MOCVD process performs preliminary action by forming the lower portion and establishing the basic structure before the MBE process begins. This preliminary preparation allows the subsequent MBE process to focus solely on precise upper portion formation, making the overall complex process more manageable and effective.
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 allows for precise control of the dimensions of the active zone, reducing wavelength dispersion of the radiation emitted by the light-emitting diodes and improving the consistency of the emitted light.
Implementation Method 1
The upper portions are formed by vapor deposition at a pressure of less than 1.33 mPa
Implementation Method 2
for the formation of the upper portions, the temperature of the upper portions is between 700°C and 850°C
Data Source
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AI summary
The present description relates to a method for manufacturing an optoelectronic device (60) comprising light-emitting diodes (LEDs), the method comprising the formation of three-dimensional semi-conductor elements (26) as a III-V compound, each comprising a lower portion (62) and an upper portion (64) and, for each semi-conductor element, the formation of an active zone (40) which covers the top (30) of the upper portion and the formation of at least one semi-conductive layer (44) of the III-V compound which covers the active zone. The upper portions are formed by vapour deposition at a pressure of less than 1.33 mPa.