Optical device including three-coupled quantum well structure having asymmetric multi-energy levels
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Solution Overview
Problem
Existing optical devices with three-coupled quantum well structures require high driving voltages to maintain high light absorption intensity, which can lead to performance degradation and increased power consumption.
Innovation Solution
A three-coupled quantum well structure with asymmetric multi-energy levels is designed, featuring a second quantum well layer with a lower energy band gap than the first and third quantum well layers, allowing for reduced driving voltage while maintaining high light absorption intensity through optimized layer thicknesses and material compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional three-coupled quantum well structure is used, then high light absorption intensity can be achieved, but high driving voltage is required
Solution Approach 1:
The patent applies asymmetry by designing the three-coupled quantum well structure with non-uniform well depths and asymmetric coupling barriers. Specifically, the first, second, and third quantum well layers have different depths, and the coupling barriers between them are asymmetrically positioned and sized. This asymmetric configuration creates favorable energy level alignment that enhances light absorption intensity while reducing the driving voltage required to achieve the desired optical modulation, directly resolving the technical contradiction between high light absorption and low driving voltage.
Solution Approach 2:
The patent employs parameter changes by systematically optimizing multiple structural parameters of the quantum well layers including thickness, material composition, and energy band gaps. The first quantum well layer has a first thickness and first energy band gap, the second has a second thickness and second energy band gap, and the third has a third thickness and third energy band gap. By carefully tuning these parameters, the structure achieves enhanced light absorption intensity at reduced driving voltage, resolving the contradiction between these two performance metrics.
2Illumination intensity
If high driving voltage is applied to maintain high light absorption intensity, then light absorption performance is improved, but power consumption increases
Solution Approach 1:
The asymmetric design of the quantum well structure with non-uniform depths and asymmetric coupling barriers creates optimized energy level alignment that enhances light absorption efficiency. This allows the device to achieve high light absorption intensity at lower driving voltages, thereby reducing power consumption while maintaining performance, directly addressing the contradiction between light absorption intensity and power consumption.
Solution Approach 2:
By optimizing the thickness and energy band gap parameters of each quantum well layer, the patent achieves a configuration where the first, second, and third quantum well layers have progressively optimized parameters. This parameter optimization enables high light absorption intensity to be achieved at reduced driving voltages, thereby lowering power consumption while maintaining high light absorption performance.
3Illumination intensity
If high driving voltage is used to maintain light absorption, then optical performance is maintained, but device reliability degrades
Solution Approach 1:
The asymmetric quantum well structure with non-uniform well depths and asymmetric coupling barriers creates optimized energy level alignment that enhances light absorption at lower electric fields. This reduces the stress and degradation mechanisms associated with high voltage operation, thereby improving device reliability while maintaining high light absorption intensity, directly resolving the contradiction between these two parameters.
Solution Approach 2:
By systematically optimizing the thickness and energy band gap parameters of the three quantum well layers, the patent achieves a configuration that maximizes light absorption efficiency at reduced operating voltages. This parameter optimization reduces electrical stress and degradation, thereby improving device reliability while maintaining high light absorption intensity, resolving the contradiction between performance and reliability.
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 proposed structure achieves high light absorption intensity at lower driving voltages, enhancing the performance and reducing power consumption in optical devices such as optical modulators and light-emitting diodes.
Implementation Method 1
Proposed may be a concept for obtaining a high light modulating property at a low driving voltage in a substrate transmissive optical modulator (optical shutter) by using light electro-absorption based on a quantum confined stark effect.
Data Source
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AI summary
Provided is an optical device including an active layer, which includes two outer barriers and a coupled quantum well between the two outer barriers. The coupled quantum well includes a first quantum well layer, a second quantum well layer, a third quantum well layer, a first coupling barrier between the first quantum well layer and the second quantum well layer, and a second coupling barrier between the second quantum well layer and the third quantum well layer. The second quantum well layer is between the first quantum well layer and the third quantum well layer. An energy band gap of the second quantum well layer is less than an energy band gap of the first quantum well layer, and an energy band gap of the third quantum well layer is equal to or less than the energy band gap of the second quantum well layer.