Semiconductor Light-Emitting Device With Reflective Electrode And Surface Asperity
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Solution Overview
Problem
Current semiconductor light-emitting devices, such as LEDs, face limitations in achieving high light emission efficiency due to challenges in improving internal quantum efficiency and light extraction efficiency, despite existing techniques like surface asperity configurations in n-type GaN layers.
Innovation Solution
A semiconductor light-emitting device configuration is introduced, featuring a first semiconductor layer with a surface asperity, a light-emitting layer between the semiconductor layers, and a third semiconductor layer with lower impurity concentration, where the first electrode is in contact with the surface asperity and reflective, enhancing light extraction efficiency by varying the incident angle of emission light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a surface asperity is provided on the n-type GaN layer, then light extraction efficiency is improved, but internal quantum efficiency remains insufficient
Solution Approach 1:
The patent applies local quality by creating surface asperities specifically on the n-type GaN layer at the light extraction surface, while maintaining different impurity concentrations in different semiconductor layers. The n-type GaN layer has a first impurity concentration, while another semiconductor layer has a second impurity concentration lower than the first, optimizing each region for its specific function (light extraction vs. light emission).
Solution Approach 2:
The patent changes physical parameters by controlling impurity concentrations in different semiconductor layers. By setting the impurity concentration of the n-type GaN layer higher than that of another semiconductor layer, the patent optimizes both electrical properties (for light extraction) and optical properties (for light emission), thereby improving both light extraction efficiency and internal quantum efficiency simultaneously.
2Power
If the first electrode is made reflective to increase light extraction, then optical output power improves, but device complexity increases
Solution Approach 1:
The first electrode serves multiple functions: it provides electrical contact to the n-type GaN layer and simultaneously acts as a reflective surface for light extraction. By combining the electrical contact function and light reflection function in a single component, the patent avoids increasing device complexity while improving optical output power through enhanced light extraction efficiency.
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 significantly increases light extraction efficiency by effectively redirecting and reflecting emission light, leading to a more efficient semiconductor light-emitting device with improved optical output power.
Implementation Method 1
The first electrode is in contact with the first surface asperity through the opening, and reflective to emission light emitted from the light-emitting layer
Implementation Method 2
enhancing light extraction efficiency by varying the incident angle of emission light
Data Source
AI summary
According to one embodiment, a semiconductor light-emitting device includes a first semiconductor layer, a second semiconductor layer, a light-emitting layer, a third semiconductor layer and a first electrode. The first semiconductor layer of a first conductivity type has a first major surface provided with a first surface asperity. The second semiconductor layer of a second conductivity type is provided on an opposite side of the first semiconductor layer from the first major surface. The light-emitting layer is provided between the first and second semiconductor layers. The first semiconductor layer is disposed between a third semiconductor layer and the light-emitting layer. The third semiconductor layer has an impurity concentration lower than an impurity concentration of the first semiconductor layer, and includes an opening exposing the first surface asperity. The first electrode is in contact with the first surface asperity through the opening, and reflective to emission light emitted from the light-emitting layer.