Cone-Shaped Quantum Well Photodetector for Wide Spectral Tuning
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Solution Overview
Problem
Photoelectric elements with quantum well structures are typically tuned to a single wavelength, limiting their ability to operate across a wider spectral range without requiring high voltages.
Innovation Solution
A cone-shaped quantum well structure composed of alternating layers of cadmium telluride and lead telluride, where the lead telluride layer's thickness varies radially, allowing for a wide frequency band or wavelength range operation, and an optical element for focusing radiation onto specific areas of the quantum well, enabling selection of operational wavelengths without high voltage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quantum well structure is tuned to a single wavelength for detection, then detection sensitivity at that wavelength is improved, but the spectral range of operation is limited
Solution Approach 1:
The patent applies local quality by creating radial variation in the active layer thickness within the quantum well structure. The thickness varies from the center to the periphery of the active layer, with different thickness regions corresponding to different wavelengths. This allows a single detector structure to detect multiple wavelengths simultaneously, with each radial position contributing to sensitivity at its corresponding wavelength.
Solution Approach 2:
The patent transitions from a uniform thickness quantum well structure to a radially varying thickness structure. By introducing radial dimensionality variation in the active layer thickness, the detector can respond to a continuous spectrum of wavelengths rather than a single wavelength, effectively using the radial dimension to encode spectral information.
2Adaptability or versatility
If the active layer thickness is increased to detect longer wavelengths, then the wavelength range is extended, but the device complexity increases
Solution Approach 1:
The patent merges multiple detection functions into a single quantum well structure by implementing radial thickness variation. Instead of requiring separate detectors or complex multi-layer structures for different wavelengths, the invention combines all wavelength detection capabilities within one active layer whose thickness varies continuously from the center to the periphery, simplifying the overall device architecture.
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
Enables detection and generation of radiation across a wide spectral range from 0.775 μm to 6.5 μm, eliminating the need for high voltages and allowing for tunable sensitivity by varying the thickness of the lead telluride layer, while maintaining axial symmetry for compatibility with optical systems.
Implementation Method 1
The layer of lead telluride has a thickness varying radially in a plane, perpendicular to the first axis, forming at least a part of a lateral side of a cone. Varying thickness of lead telluride layer allows a use of photoelectric effect in a wide frequency band or wavelength range.
Data Source
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AI summary
Axial active photoelectric element having a layered structure stacked along a first axis (O) and comprising a first electrode (141) and a second electrode (142). The layered structure comprises a substrate (110) and a structure of a quantum well. The quantum well structure is a layer of lead telluride (130) which is an active layer and disposed between two layers of cadmium telluride (121, 122). The layer of lead telluride (130) has a radially varying thickness and forms at least a part of a lateral side of a cone.