Semiconductor Light Emitting Device Quantum Well Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The response speed of semiconductor light emitting devices is limited by their junction capacitance, which is larger than that of light receiving devices, making it difficult to improve their speed for high-speed signal transmission in light coupling devices.
Innovation Solution
A semiconductor light emitting device with a quantum well structure comprising alternately laminated well and barrier layers, where each well layer is less than 15 nm thick and each barrier layer is between 15 nm to 50 nm thick, reducing junction capacitance and enhancing light output while maintaining low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the light emitting device uses a conventional structure, then it can maintain stable light emission, but the junction capacitance is large which limits the response speed
Solution Approach 1:
The active layer is segmented into multiple quantum well structures with alternating well layers and barrier layers. Each quantum well layer has a thickness of 5 nm or less, while barrier layers are 10 nm or more thick. This segmentation reduces the overall thickness of the light emitting layer, thereby reducing junction capacitance and improving response speed while maintaining light emission stability through the periodic structure.
Solution Approach 2:
The patent changes the thickness parameters of the quantum well layers and barrier layers to optimize performance. By setting well layer thickness to 5 nm or less and barrier layer thickness to 10 nm or more, the device achieves reduced junction capacitance and improved response speed while maintaining adequate light output through careful parameter selection.
2Speed
If the well layers are made thinner to reduce capacitance, then response speed improves, but light output may decrease
Solution Approach 1:
The patent optimizes the thickness parameter of well layers to be 5 nm or less, which reduces junction capacitance and improves response speed. Simultaneously, the barrier layer thickness is set to 10 nm or more to maintain adequate light output by preventing carrier leakage while allowing sufficient carrier confinement for light generation.
Solution Approach 2:
The patent uses a composite quantum well structure with alternating layers of different materials (e.g., InGaAsP wells and InP barriers) with different bandgap energies. This composite structure enables thin well layers to confine carriers effectively while the barrier layers prevent carrier leakage, maintaining light output despite reduced well layer thickness.
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 reduces junction capacitance, shortens light emitting delay times, and maintains high quantum efficiency, allowing for faster response speeds and reduced power consumption, enabling efficient high-speed signal transmission in light coupling devices.
Implementation Method 1
a quantum well structure made by alternately laminating n (an integer of not less than 1) well layers and (n+1) barrier layers
Implementation Method 2
The light emitting layer includes a quantum well structure made by alternately laminating n (an integer of not less than 1) well layers and (n+1) barrier layers and emits light with a peak wavelength of 650 nm to 1000 nm
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a semiconductor laminated body provided on a semiconductor substrate. The semiconductor laminated body includes a light emitting layer. The light emitting layer includes a quantum well structure made by alternately laminating n (an integer of not less than 1) well layers and (n+1) barrier layers and emits light with a peak wavelength of 650 nm to 1000 nm. Each of the well layers has a thickness of smaller than 15 nm. Each of the barrier layers has a thickness of 15 nm to 50 nm.