Semiconductor Laser Transparent Conductive Cladding
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Solution Overview
Problem
High power output in semiconductor lasers leads to increased heat generation, necessitating a reduction in drive voltage and light absorption to improve efficiency.
Innovation Solution
A semiconductor laser design featuring a semiconductor stack with a transparent conductive material in the upper cladding layer and low-concentration impurity layers with specific impurity concentrations and thicknesses, along with a ridge structure, to minimize light absorption and confine light effectively without the need for thick AlGaN cladding layers doped with Mg.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high power output is achieved to increase luminance, then light output characteristics are improved, but heat generation increases
Solution Approach 1:
The patent changes the impurity concentration parameter to 5.0×10^17 cm^-3 or less and controls the total thickness to 250 nm or more and 1000 nm or less, optimizing the balance between electrical conductivity and light absorption to reduce heat generation while maintaining high power output
Solution Approach 2:
The transparent conductive material serves as an intermediary between the contact layer and the light waveguide region, providing electrical connection while minimizing light absorption and heat generation through optimized positioning and material properties
2Stability of the object's composition
If thick AlGaN cladding layers doped with Mg are used to confine light, then light confinement is improved, but light absorption increases and drive voltage rises
Solution Approach 1:
The patent extracts the light confinement function from the traditional thick AlGaN cladding layer and implements it through a transparent conductive material positioned away from the light waveguide region, eliminating the need for Mg doping and reducing light absorption
Solution Approach 2:
The transparent conductive material is positioned locally away from the light waveguide region, providing electrical functionality in one area while maintaining optical transparency in the light propagation area, achieving both electrical conductivity and light confinement without conflict
3Stability of the object's composition
If traditional cladding layer structure is used to confine light, then light confinement is achieved, but drive voltage is high
Solution Approach 1:
The patent changes the impurity concentration to 5.0×10^17 cm^-3 or less and optimizes the thickness to 250 nm or more and 1000 nm or less, reducing electrical resistance and drive voltage while maintaining effective light confinement through the transparent conductive material structure
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 design reduces drive voltage and enhances electric power conversion efficiency by minimizing light absorption and maintaining stable laser operation, achieving higher light output and improved power conversion efficiency compared to conventional nitride-based semiconductor lasers.
Implementation Method 1
light is confined in a stacking direction by the second cladding layer including the transparent conductive material
Implementation Method 2
the light is also confined in a transverse direction
Implementation Method 3
This allows for reduction of the light absorption by the transparent conductive material
Data Source
AI summary
A semiconductor laser according to one embodiment of the present disclosure includes a semiconductor stack. The semiconductor stack includes, in the following order, a first cladding layer, an active layer, one or a plurality of low-concentration impurity layers, a contact layer, and a second cladding layer that includes a transparent conductive material. The semiconductor stack further has, in a portion including the contact layer, a ridge extending in a stacked in-plane direction. Each low-concentration impurity layer has an impurity concentration of 5.0×1017 cm−3 or less, and a total thickness of the low-concentration impurity layer is 250 nm or more and 1000 nm or less. A distance between the second cladding layer and the low-concentration impurity layer closest to the second cladding layer is 150 nm or less.