Semiconductor Light-Emitting Device With Segmented Well Layers
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Solution Overview
Problem
Semiconductor lasers with nitride semiconductors face challenges in light emission intensity due to spatial separation of electrons and holes caused by spontaneous and piezoelectric polarization, leading to inefficient transport between well layers, which impairs light emission efficiency.
Innovation Solution
A semiconductor light-emitting device with a multiple well structure where the band gap inclination angle of the second well layer relative to the p-type semiconductor layer is smaller than that of the first well layer relative to the n-type semiconductor layer, facilitating improved electron and hole transport while reducing spatial separation, thereby enhancing light emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the band gap is continuously inclined in a well layer to reduce spatial separation of electrons and holes, then light emission intensity is improved, but transport of electrons or holes between well layers becomes difficult
Solution Approach 1:
The active layer is divided into multiple discrete well layers (first well layer and second well layer) with different band gap inclination angles. Each well layer is segmented to have specific inclination characteristics: the first well layer has a larger inclination angle to reduce spatial separation, while the second well layer has a smaller inclination angle to facilitate carrier transport, thereby resolving the contradiction between light emission intensity and carrier transport efficiency
Solution Approach 2:
Different regions (well layers) of the active layer are given different local properties by assigning different band gap inclination angles to different well layers. The first well layer located near the n-type semiconductor layer has a larger inclination angle optimized for reducing electron-hole separation, while the second well layer located near the p-type semiconductor layer has a smaller inclination angle optimized for hole transport, achieving localized optimization of both light emission and carrier transport
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 decreases the threshold current and improves light emission efficiency by reducing energy barriers for hole transport, resulting in a more efficient semiconductor light-emitting device.
Implementation Method 1
In the nitride semiconductor, a band in a well layer has an inclination by spontaneous polarization or piezoelectric polarization. This causes an issue that electrons and holes are spatially separated to decrease light emission intensity.
Implementation Method 2
semiconductor lasers of red, green, and blue that are three primary colors of light have been all achieved
Data Source
AI summary
A semiconductor light-emitting device according to an embodiment of the present disclosure includes an n-type semiconductor layer, a p-type semiconductor layer, and an active layer provided between the n-type semiconductor layer and the p-type semiconductor layer and including a plurality of well layers. In the plurality of well layers included in the active layer, a band gap inclination angle θ1 of a second well layer located relatively close to the p-type semiconductor layer is smaller than a band gap inclination angle θ2 of a first well layer located relatively close to the n-type semiconductor layer.