Three-Dimensional Quantum Dots for Wavelength Extension
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Solution Overview
Problem
Optoelectronic devices with III-V or II-VI compound semiconductor materials face limitations in wavelength extension due to lattice parameter differences, leading to non-radiative defects and decreased quantum efficiency when the atomic percent of indium exceeds a threshold.
Innovation Solution
Incorporating quantum dots made of a mixture of III-V or II-VI compounds and an additional element, such as InxAlyGa1-x-yN, at the seams between angled facets of three-dimensional semiconductor elements, allowing for emission or reception of electromagnetic radiation at different wavelengths, thereby overcoming the limitations of single quantum well structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the atomic percent of indium in the quantum well is increased to achieve higher wavelength emission, then the wavelength of emitted radiation increases, but lattice parameter differences cause non-radiative defects and quantum efficiency decreases
Solution Approach 1:
The patent changes the structural parameter from a planar quantum well to vertically stacked quantum wells with different orientations. This parameter change allows the system to achieve higher wavelengths by utilizing quantum confinement effects in the vertical stacking direction while maintaining lateral lattice matching, thus avoiding dislocation formation and preserving quantum efficiency.
Solution Approach 2:
The patent transitions from a two-dimensional quantum well structure to a three-dimensional stacked quantum well structure. By adding the vertical stacking dimension, the invention enables wavelength extension through inter-well coupling and quantum confinement in the vertical direction, while each individual well maintains lateral lattice matching to prevent dislocations.
2Length of stationary object
If traditional quantum well structures are used to achieve long wavelength emission, then material composition must be changed (increasing indium content), but this leads to lattice mismatch and formation of non-radiative defects
Solution Approach 1:
The patent segments the quantum well structure into multiple thin wells stacked vertically, separated by barrier layers. This segmentation allows each individual well to maintain thin thickness and lateral lattice matching, avoiding dislocation formation, while the stack collectively achieves longer wavelength emission through quantum confinement and inter-well coupling effects.
Solution Approach 2:
The patent creates a composite structure consisting of multiple quantum wells with different orientations stacked vertically, separated by barrier layers. This composite architecture combines the advantages of quantum confinement in each well with the wavelength extension effect of the stacked configuration, achieving long wavelength emission without the harmful effects of lattice mismatch.
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 the emission or reception of electromagnetic radiation at higher wavelengths with improved quantum efficiency by forming quantum dots that differ in composition from traditional quantum wells, reducing defects and enhancing the operational range of optoelectronic devices.
Implementation Method 1
quantum dots at at least some of the seams between facets... being capable of emitting or of receiving a first electromagnetic radiation at a first wavelength
Data Source
AI summary
An optoelectronic device including three-dimensional semiconductor elements predominantly made of a first compound selected from among the group consisting of Compounds III-V, Compounds II-VI, and Compounds IV. Each semiconductor element defines, optionally with insulating portions partially covering said semiconductor element, at least one first surface including contiguous facets angled relative to each other. The optoelectronic device includes quantum dots at least some of the seams between the facets. The quantum dots are predominantly made of a mixture of the first compound and an additional element and are suitable for emitting or receiving a first electromagnetic radiation at a first wavelength.