Surface-Emitting Laser Quantum Well Thickness for Strain Control
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Solution Overview
Problem
Existing surface emitting semiconductor lasers face challenges in maintaining optical confinement and reducing crystal strain due to lattice mismatch, particularly when the quantum well layer thickness approaches the critical film thickness, affecting the efficiency and stability of the laser operation.
Innovation Solution
The laser design includes a quantum well layer with a thickness thinner than the critical film thickness by a predetermined margin, combined with a barrier layer thickness adjusted accordingly, to enhance optical confinement and reduce crystal strain, using materials like InGaAs and GaAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the quantum well layer thickness is increased to approach the critical film thickness, then the light emission intensity is improved, but the crystal strain due to lattice mismatch increases causing dislocation propagation
Solution Approach 1:
The patent changes the thickness parameter of the quantum well layer, setting it to be thinner than the critical film thickness by a predetermined margin. This parameter adjustment resolves the contradiction by finding an optimal thickness value that maintains sufficient light emission intensity while preventing excessive crystal strain and dislocation propagation that would occur at or near the critical thickness.
2Stability of the object's composition
If the quantum well layer thickness is increased, then the optical confinement is improved, but the lattice mismatch strain increases
Solution Approach 1:
The patent applies parameter change by optimizing the quantum well layer thickness to be below the critical film thickness. This creates an optimal balance where the layer is thick enough to provide adequate optical confinement for laser operation, yet thin enough to prevent excessive lattice mismatch strain that would lead to dislocation and degrade structural stability.
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 increased optical confinement, improved light emission intensity, and reduced dislocation propagation, enhancing the performance and efficiency of the semiconductor laser.
Implementation Method 1
a light emitting layer that is disposed between the first semiconductor multilayer film reflective mirror and the second semiconductor multilayer film reflective mirror, emits light, and is configured by alternately stacking a quantum well layer containing at least In, Ga, and As and a barrier layer
Implementation Method 2
a first semiconductor multilayer film reflective mirror stacked on the substrate; a second semiconductor multilayer film reflective mirror that includes a current confinement layer and is stacked on the first semiconductor multilayer film reflective mirror
Data Source
AI summary
A surface emitting semiconductor laser includes a substrate; a first semiconductor multilayer film reflective mirror stacked on the substrate; a second semiconductor multilayer film reflective mirror that includes a current confinement layer and is stacked on the first semiconductor multilayer film reflective mirror; and a light emitting layer that is disposed between the first semiconductor multilayer film reflective mirror and the second semiconductor multilayer film reflective mirror, emits light, and is configured by alternately stacking a quantum well layer containing at least In, Ga, and As and a barrier layer, in which a thickness of the quantum well layer is thinner than a critical film thickness by a predetermined margin.