Optical Semiconductor Device Multilayer Stacked Body
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Solution Overview
Problem
Current optical semiconductor devices, such as LEDs and laser diodes, face challenges in achieving high efficiency and luminance due to suboptimal light emission characteristics, particularly in the stacking structure and material composition of their active layers.
Innovation Solution
The optical semiconductor device incorporates a multilayer stacked body with alternating thick and thin film layers, including a nitride semiconductor material, forming a multiple quantum well (MQW) structure with specific barrier and well layers to enhance light emission efficiency and luminance, where the multilayer stacked body is directly under each well layer to ensure uniform characteristics and carrier confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional single-layer active structure is used, then the device complexity is low, but the light emission efficiency and luminance are insufficient
Solution Approach 1:
The active layer is segmented into multiple functional sub-layers including a multilayer stacked body with alternating thick and thin film layers, barrier layers, and well layers. This segmentation allows each sub-layer to perform specific functions (carrier confinement, recombination, light emission) thereby improving light emission efficiency while managing complexity through functional specialization
Solution Approach 2:
Different regions of the active layer are assigned different material compositions and thicknesses to optimize local properties. The multilayer stacked body has alternating thick/thin film layers with specific thickness ratios, barrier layers have specific width ranges, and well layers have optimized thicknesses. This local quality optimization enhances carrier confinement and recombination efficiency at critical interfaces while maintaining overall device performance
2Illumination intensity
If the number of layers and film thickness are increased to improve light emission, then the luminance increases, but the total layer count and device complexity increase
Solution Approach 1:
The device employs composite material structures including a multilayer stacked body with alternating thick and thin film layers of different nitride semiconductor compositions. This composite structure achieves enhanced light emission and luminance through improved carrier confinement and recombination at the material interfaces, while the optimized thickness ratios and alternating pattern prevent excessive layer multiplication by maximizing the functional efficiency of each layer
Solution Approach 2:
The invention optimizes specific parameters including the thickness of thin film layers (not more than thick film layers), the width of barrier layers (specific range), and the thickness of well layers. These parameter optimizations ensure that each layer contributes maximally to light emission efficiency, achieving high luminance without requiring an excessive number of layers. The parameter changes are designed to balance carrier confinement, recombination efficiency, and optical output
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 results in significantly improved light emission efficiency and luminance, with the optical semiconductor device achieving peak photo-luminescence intensity 8.6 times higher than a reference example without the multilayer stacked body and 2.6 times higher than another reference example with a different stacking configuration, while reducing the total number of layers and film thickness.
Implementation Method 1
The multilayer stacked body includes a plurality of thick film layers and a plurality of thin film layers alternately stacked in the direction. A multiple quantum well (MQW) structure with specific barrier and well layers to enhance light emission efficiency and luminance
Implementation Method 2
A light emitting diode (LED) which is a semiconductor light emitting device using a nitride semiconductor
Implementation Method 3
achieving peak photo-luminescence intensity 8.6 times higher than a reference example
Data Source
AI summary
According to one embodiment, an optical semiconductor device includes an n-type semiconductor layer, a p-type semiconductor layer, and a functional part. The functional part is provided between the n-type semiconductor layer and the p-type semiconductor layers. The functional part includes a plurality of active layers stacked in a direction from the n-type semiconductor layer toward the p-type semiconductor layer. At least two of the active layers include a multilayer stacked body, an n-side barrier layer, a well layer and a p-side barrier layer. The multilayer stacked body includes a plurality of thick film layers and a plurality of thin film layers alternately stacked in the direction. The n-side barrier layer is provided between the multilayer stacked body and the p-type layer. The well layer is provided between the n-side barrier layer and the p-type layer. The p-side barrier layer is provided between the well layer and the p-type layer.