Quantum Well Light Detector with Foreign Atoms for Infrared Sensing
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Solution Overview
Problem
Current photodetection technologies face challenges in detecting weak and long wavelength photons, particularly in the infrared range, due to high noise levels and difficulty in stabilizing avalanche amplification, and require cryogenic temperatures for efficient operation.
Innovation Solution
A light detection system utilizing a quantum well structure with foreign atoms like nitrogen or bismuth, inducing excited and fundamental bound states, allows for efficient detection of photons with wavelengths from 1 micron to 10 microns at room temperature, using a quantum well structure with quantum barriers to enhance absorption and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If avalanche amplification is used to detect weak optical signals, then sensitivity is improved, but internal noise level and response time increase rapidly with multiplication factor
Solution Approach 1:
The patent introduces an optical cavity as an intermediary element that resonates at specific wavelengths to enhance the interaction between incident photons and the quantum well structure. This cavity-mediated approach allows for improved detection sensitivity without relying solely on high multiplication factor avalanche amplification, thereby reducing internal noise levels while maintaining detection capability for weak optical signals
Solution Approach 2:
The patent employs quantum well structures with carefully engineered bandgap energies and well depths to optimize photon absorption at specific wavelengths. By adjusting the quantum well parameters (width, depth, material composition) and operating temperature, the system achieves high sensitivity detection without requiring excessive avalanche multiplication, thus controlling the noise level
2Measurement precision
If interband absorption detectors are used for infrared detection, then detection capability is achieved, but cryogenic temperatures are required for operation
Solution Approach 1:
The patent utilizes quantum well structures with engineered bandgap energies that are optimized for infrared photon absorption. By carefully selecting the quantum well width, depth, and material composition (e.g., InGaAs/InP systems), the detection threshold can be tuned to specific infrared wavelengths while maintaining operation at elevated temperatures through proper energy level alignment
Solution Approach 2:
The patent employs composite semiconductor structures combining different materials (e.g., InGaAs quantum wells embedded in InP barriers) to create quantum well systems with tailored optical and electrical properties. This composite approach enables infrared detection capability while the specific material selection allows operation at higher temperatures compared to conventional single-material infrared detectors
3Temperature
If quantum well structure with foreign atoms is used, then room temperature operation is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs computational optimization methods to determine the optimal quantum well parameters (width, depth, composition) that achieve room temperature operation. By using advanced simulation and modeling during the design phase, the manufacturing tolerances can be optimized to accommodate practical fabrication variations while maintaining the desired detection performance at elevated temperatures
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 system achieves high responsivity and gain while maintaining low dark current, enabling effective detection of infrared light without the need for cryogenic temperatures, with normalized detectivity exceeding 10^12 cm(Hz)^0.5/W at room temperature.
Implementation Method 1
Another technology is based on intersubband (ISB) transitions in heterostructures in a configuration known as Quantum Well Infrared Photodetectors (QWIP), wherein the photodetection mechanism is via absorption between subbands rather than between the valence and conduction bands.
Implementation Method 2
The active region comprises a quantum well structure having a quantum well between quantum barriers
Implementation Method 3
The quantum well comprises foreign atoms inducing an excited bound state at an energy level which is above an energy level characterizing the quantum barriers
Data Source
AI summary
A light detection system which comprises an active region between a back contact layer and a front contact layer is disclosed. The active region comprises a quantum well structure having a quantum well between quantum barriers, wherein the quantum well comprises foreign atoms that induce an excited bound state at an energy level which is above an energy level characterizing the quantum barriers.