Semiconductor Laser Current Narrowing Window Hole Leakage
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Solution Overview
Problem
Conventional semiconductor lasers experience inefficiencies in hole injection due to wide spreading of holes through the first p-type InP cladding layer, leading to increased useless hole-leakage current, and require multiple crystal growth steps increasing manufacturing costs.
Innovation Solution
A semiconductor laser design with a current narrowing window at the center of the second n-type blocking layer or first p-type cladding layer, allowing hole current to pass through, reducing hole-leakage current and eliminating the need for additional crystal growth steps by integrating the blocking layers in a single growth process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If holes are allowed to flow through the first p-type InP cladding layer toward the active layer, then hole injection is achieved, but holes spread widthwise causing increased hole-leakage current that does not contribute to light emission
Solution Approach 1:
The patent applies local quality by creating a current narrowing window with different electrical properties in a specific location (center of the second n-type blocking layer) while maintaining the original structure elsewhere. This localized modification restricts hole flow to a narrow path directly over the active layer, preventing widthwise spreading and reducing hole-leakage current without affecting overall hole injection efficiency
Solution Approach 2:
The patent segments the hole flow path by introducing a current narrowing window that divides the wide hole leakage path into a narrower, controlled path. This segmentation confines holes to a specific trajectory through the second n-type blocking layer, ensuring they reach the active layer efficiently while preventing lateral spreading that would cause energy loss
2Power
If n-type InP blocking layers are grown twice separately to narrow the hole leakage path, then hole injection efficiency is improved, but the number of production steps and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of multiple blocking layers into a single second n-type blocking layer with an integrated current narrowing window. Instead of requiring separate growth steps for multiple blocking layers, the invention achieves the same hole confinement effect through one blocking layer with a strategically positioned window, thereby reducing production steps while maintaining hole injection efficiency
Solution Approach 2:
The patent changes the structural parameters of the second n-type blocking layer by introducing a current narrowing window with specific dimensions and position. This parameter modification allows the single blocking layer to perform the hole-confining function that previously required multiple layers, reducing manufacturing complexity without sacrificing 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
The design enhances hole injection efficiency, reduces useless hole-leakage current, and maintains productivity while lowering manufacturing costs by simplifying the crystal growth process.
Implementation Method 1
a current narrowing window for allowing a hole current to pass therethrough is provided in and at a center of the second n-type blocking layer placed at the top of the ridge
Implementation Method 2
In the active layer, electrons supplied from the n-type InP cladding layer are recombined with holes supplied from the second p-type InP cladding layer, making it possible to achieve light power and gain
Data Source
AI summary
What is provided are: an active-layer ridge which is composed of an n-type cladding layer, an active layer, a first p-type cladding layer and a second n-type blocking layer that are stacked in this order on an n-type InP substrate, and which is formed to project from a position lower than the active layer; burying layers by which both side portions of the active-layer ridge are buried up to a position higher than the active layer; first n-type blocking layers which are each stacked on a front-surface side of each of the burying layers, to be placed on the both sides of the ridge; and a second p-type cladding layer by which an end portion of the active-layer ridge and the first n-type blocking layers are buried thereunder; wherein a current narrowing window for allowing a hole current to pass therethrough is provided in and at a center of the second n-type blocking layer placed at a top of the active-layer ridge.