Quantum Well Carrier Trapping to Reduce Auger Recombination
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Solution Overview
Problem
Auger recombination is a non-radiative process that reduces the efficiency and increases the threshold current of semiconductor lasers, making them sensitive to temperature variations.
Innovation Solution
Incorporating a quantum well structure that traps either electrons or holes, creating a charge imbalance in the active region to reduce Auger recombination, with the second region positioned close enough to affect charge balance but far enough to prevent recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional semiconductor laser structures are used, then the device is simpler to manufacture, but Auger recombination increases threshold current and reduces efficiency
Solution Approach 1:
The active region is segmented into multiple quantum wells separated by barrier layers. This segmentation allows independent optimization of each quantum well for carrier confinement while the barrier layers provide spatial separation that reduces Auger recombination events between electrons and holes, thereby reducing energy loss while maintaining manufacturability through standard quantum well growth techniques
Solution Approach 2:
Different regions of the semiconductor structure are given different compositions and properties. The quantum wells have specific bandgap energies optimized for carrier confinement, while the barrier layers have higher bandgap energies optimized for blocking carriers and reducing Auger recombination. This local differentiation of material properties reduces energy loss without requiring complete structural redesign
2Loss of energy
If quantum well structures are added to reduce Auger recombination, then energy efficiency improves, but device complexity increases
Solution Approach 1:
The active region is divided into multiple quantum wells with barrier layers between them. This segmentation reduces Auger recombination by spatially separating electron and hole confinement regions, thereby reducing energy loss. The segmented structure uses standard semiconductor growth techniques, making the complexity manageable through established fabrication processes
Solution Approach 2:
The device uses composite material structures combining different semiconductor alloys with specific bandgap energies. The quantum wells use materials with lower bandgap for carrier confinement, while barrier layers use materials with higher bandgap to block carriers and reduce Auger recombination. This composite approach reduces energy loss while leveraging well-understood material systems
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
Reduces Auger recombination by altering the charge balance in the active region, thereby decreasing the threshold current and enhancing the efficiency of semiconductor lasers.
Implementation Method 1
at least one second region comprising a quantum well structure which is configured to preferentially trap either electrons or holes
Implementation Method 2
electrons and holes recombine in the active region to produce photons when a voltage is applied across the device
Implementation Method 3
Auger recombination is a non-radiative process which reduces the efficiency of a semiconductor laser and increases its threshold current
Data Source
AI summary
A semiconductor optical device (40, 50, 60) comprises a first region 42 comprising an active region configured such that electrons and holes recombine in the active region to produce photons when a voltage is applied to the device. The device comprises at least one second region (43, 44, 53, 54, 62, 63) comprising a quantum well structure which is configured to trap electrons only, to trap holes only, or to trap different amounts of electrons and holes. The second region is arranged at a distance from the first region which is sufficiently close to the first region such that a charge imbalance develops in the first region when a voltage is applied to the device, thereby to reduce Auger recombination in the first region.