Multi-Color LED Structures with Intermediate Carrier Blocking Layers
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Solution Overview
Problem
Conventional semiconductor light-emitting diodes and laser diodes face inefficiencies due to inhomogeneous charge carrier distribution in multi-layer active regions, leading to increased nonradiative Auger recombination, carrier leakage, and optical losses, which affect their performance and efficiency, particularly in III-nitride based devices.
Innovation Solution
Incorporating intermediate carrier blocking layers (IBLs) with specific compositions and doping levels into the active region of semiconductor light-emitting structures to balance electron and hole transport, control carrier capture rates, and achieve uniform carrier population distribution, thereby enhancing injection efficiency and reducing overflow and recombination losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple quantum wells are used to spread injected carriers, then nonradiative Auger recombination loss decreases, but inhomogeneous distribution of charge carriers occurs
Solution Approach 1:
The patent introduces electron blocking layers as intermediary structures between quantum wells to mediate carrier transport. These layers selectively block electrons while allowing holes to pass, thereby redistributing carriers uniformly across multiple quantum wells and preventing inhomogeneous accumulation that leads to Auger recombination loss.
Solution Approach 2:
The patent modifies the bandgap parameters of intermediate layers by adjusting aluminum composition in AlGaN barriers. By changing the bandgap energy parameter of intermediate layers, the patent controls carrier confinement and transport characteristics, achieving uniform carrier distribution across quantum wells with different energy levels.
2Device complexity
If conventional MQW design is used, then device structure is simple, but carrier injection efficiency is low due to inhomogeneous population
Solution Approach 1:
The patent segments the active region into multiple quantum wells separated by intermediate electron blocking layers. This segmentation allows independent control of carrier injection into each quantum well, improving overall injection efficiency while maintaining a modular structure that can be grown using standard epitaxial techniques.
Solution Approach 2:
The patent introduces electron blocking layers as intermediary structures between quantum wells to mediate carrier transport. These layers selectively block electrons while allowing holes to pass, thereby redistributing carriers uniformly across multiple quantum wells and preventing inhomogeneous accumulation that leads to Auger recombination loss.
3Ease of manufacture
If polar III-nitride heterostructures are used, then material growth is well-established, but built-in polarization fields cause non-uniform carrier injection
Solution Approach 1:
The patent introduces electron blocking layers as intermediary structures between quantum wells to mediate carrier transport. These layers selectively block electrons while allowing holes to pass, thereby redistributing carriers uniformly across multiple quantum wells and preventing inhomogeneous accumulation that leads to Auger recombination loss.
Solution Approach 2:
The patent modifies the bandgap parameters of intermediate layers by adjusting aluminum composition in AlGaN barriers. By changing the bandgap energy parameter of intermediate layers, the patent controls carrier confinement and transport characteristics, achieving uniform carrier distribution across quantum wells with different energy 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 use of IBLs in the active region of semiconductor light-emitters results in improved carrier injection uniformity, increased efficiency, and tunable multi-color emission capabilities, including white-light emission, by controlling carrier distribution and minimizing crystalline strain, thus overcoming the limitations of conventional designs.
Implementation Method 1
Incorporating intermediate carrier blocking layers (IBLs) with specific compositions and doping levels into the active region of semiconductor light-emitting structures to balance electron and hole transport, control carrier capture rates
Implementation Method 2
Semiconductor light emitting diode structures have become the established leaders among optical light sources
Data Source
AI summary
Disclosed herein are multi-layered optically active regions for semiconductor light-emitting devices (LEDs) that incorporate intermediate carrier blocking layers, the intermediate carrier blocking layers having design parameters for compositions and doping levels selected to provide efficient control over the carrier injection distribution across the active regions to achieve desired device injection characteristics. Examples of embodiments discussed herein include, among others: a multiple-quantum-well variable-color LED operating in visible optical range with full coverage of RGB gamut, a multiple-quantum-well variable-color LED operating in visible optical range with an extended color gamut beyond standard RGB gamut, a multiple-quantum-well light-white emitting LED with variable color temperature, and a multiple-quantum-well LED with uniformly populated active layers.