Light Emitting Device with Carbon-Doped Window Layer
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Solution Overview
Problem
Current light emitting devices face challenges in reducing operating voltage and improving light speed while maintaining reliability, particularly in GaP-based semiconductor systems where light absorption and current spreading efficiency are limited.
Innovation Solution
A light emitting device design incorporating a GaP-based semiconductor doped with carbon, featuring a conductive contact layer with increased current contact area and an omnidirectional reflector layer under a distributed Bragg reflector layer, along with a conductive contact layer with a material different from the mirror layer, to enhance light reflection and current spreading efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional conductive contact layer is used with GaP-based semiconductor, then the device structure is simple, but light absorption occurs and current spreading efficiency is limited
Solution Approach 1:
The patent introduces a window semiconductor layer as an intermediary between the GaP-based semiconductor and the conductive contact layer. This window layer has a wider bandgap than the GaP semiconductor, allowing it to be transparent to the emitted light while providing a suitable interface for the conductive contact layer, thereby reducing light absorption without requiring complex material modifications to the active layers
Solution Approach 2:
The patent employs a composite structure combining multiple semiconductor layers with different bandgap characteristics. The window semiconductor layer is formed by combining GaP with other materials (such as AlGaInP) to create a layer with specific optical and electrical properties that bridge the gap between the active semiconductor and the conductive contact layer
2Productivity
If the conductive contact layer thickness is increased to improve current spreading, then current contact area increases, but light absorption increases
Solution Approach 1:
The patent changes the key parameter of the window semiconductor layer - its dopant concentration. By heavily doping the window layer with carbon (达到1×10^19 to 1×10^21 atoms/cm³), the layer achieves high electrical conductivity and excellent current spreading capability while maintaining optical transparency, thus improving current spreading efficiency without increasing light absorption
3Reliability
If GaP-based semiconductor is doped with carbon to improve conductivity, then current spreading improves, but light absorption in conductive contact layer increases
Solution Approach 1:
The window semiconductor layer serves as a mediator that separates the carbon doping function from the light transmission function. The carbon is doped into the window layer rather than the conductive contact layer, providing the necessary electrical properties for reliable current contact while the window layer's optical properties ensure minimal light absorption
4Use of energy by moving object
If operating voltage is reduced to improve efficiency, then energy consumption decreases, but current spreading and light extraction efficiency are limited
Solution Approach 1:
The patent modifies the electrical parameters of the window semiconductor layer through heavy carbon doping, achieving high conductivity that enables efficient current spreading at lower operating voltages. Simultaneously, the optical parameters are optimized by selecting materials with appropriate bandgaps, enabling effective light extraction even at reduced voltage levels
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 solution effectively lowers operating voltage, improves light speed, and increases light extraction efficiency by reducing light absorption and enhancing current spreading, thereby improving the overall performance and reliability of the light emitting device.
Implementation Method 1
a mirror layer under the window semiconductor layer, a reflective layer under the mirror layer... an omnidirectional reflector (ODR) layer under a distributed Bragg reflector (DBR) layer provided under a GaP-based semiconductor
Implementation Method 2
The window semiconductor layer includes a phosphorus (P)-based semiconductor doped with carbon (C)... the conductive contact layer is disposed between the reflective layer and the window semiconductor layer and contacted with the second conductive semiconductor layer
Implementation Method 3
The window semiconductor layer includes a phosphorus (P)-based semiconductor doped with carbon (C), the window semiconductor layer has a dopant concentration higher than a dopant concentration of the second conductive semiconductor layer
Data Source
AI summary
Disclosed is a light emitting device including a light emitting structure including a first conductive semiconductor layer, an active layer under the first conductive semiconductor layer, and a second conductive semiconductor layer under the active layer, a first electrode electrically connected with the first conductive semiconductor layer, a mirror layer under the light emitting structure, a window semiconductor layer between the mirror layer and the light emitting structure, a reflective layer under the mirror layer, a conductive contact layer between the reflective layer and the window semiconductor layer and in contact with the second conductive semiconductor layer, and a conductive support substrate under the reflective layer. The window semiconductor layer includes a C-doped P-based semiconductor doped with a higher dopant concentration. The conductive contact layer includes material different from that of the mirror layer with a thickness thinner than that of the window semiconductor layer.