Infrared Detector Quantum Well Light Emission Amplification
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Solution Overview
Problem
Existing infrared detectors face challenges in achieving high detection sensitivity and large-area image sensors, particularly in the far-infrared wavelength range, due to limitations in material properties and manufacturing difficulties with HgCdTe and QWIPs, which result in low quantum efficiency and poor yield.
Innovation Solution
A multi-layered infrared detector structure incorporating a photo-current generating portion with a QWIP structure, a light emitting portion, and a photo-detecting portion, where electrons generated by incident infrared rays are injected into the light emitting portion to emit near-infrared and visible rays, which are then detected, enhancing sensitivity and efficiency through distributed Bragg reflection and avalanche photodiode usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HgCdTe is used for far-infrared detection, then high quantum efficiency is achieved, but manufacturing yield becomes poor due to low melting point and high vapor pressure of Hg
Solution Approach 1:
The invention changes the material composition parameters by using group III-V compound semiconductors (GaAs, AlGaAs, InGaAs) instead of HgCdTe, fundamentally altering the material system to achieve both high quantum efficiency and manufacturability. This parameter change allows standard semiconductor manufacturing processes to be used, improving yield while maintaining detection performance.
2Area of stationary object
If QWIP structure with superlattice of AlGaAs and GaAs is used, then large-area image sensors can be manufactured, but quantum efficiency becomes extremely low due to one-dimensional electron quantization
Solution Approach 1:
The invention uses a composite structure combining QWIP for far-infrared detection with a light-emitting layer and photodiode array for near-infrared detection. This composite system converts low-quantum-efficiency far-infrared photons into high-quantum-efficiency near-infrared photons, achieving high overall quantum efficiency while maintaining large-area capability.
Solution Approach 2:
The light-emitting layer acts as an intermediary that converts far-infrared radiation detected by the QWIP into near-infrared light, which is then detected by the photodiode array. This intermediary conversion process overcomes the low quantum efficiency limitation of direct far-infrared detection while preserving large-area sensor capabilities.
3Measurement precision
If conventional QWIP structure is used, then far-infrared detection is achieved, but detection sensitivity remains insufficient due to lack of signal amplification
Solution Approach 1:
The invention implements an optical feedback mechanism where the light-emitting layer receives electrical signals from the QWIP and converts them back into optical signals that are detected and amplified by the photodiode array. This feedback loop enables signal amplification and enhances detection sensitivity beyond what conventional QWIP can achieve.
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 solution improves detection sensitivity and allows for the manufacture of large-area image sensors with high quantum efficiency, effectively addressing the limitations of previous technologies by confining and amplifying near-infrared and visible rays within the detector.
Implementation Method 1
photo-current generating portion, where incident infrared rays generate electrons
Implementation Method 2
light emitting portion, where the electrons thus injected and holes recombine to emit rays
Implementation Method 3
reflection portion that reflects rays in a near-infrared range and in a visible range
Implementation Method 4
enhancing sensitivity and efficiency through distributed Bragg reflection
Implementation Method 5
photo-detecting portion that detects the rays in a near-infrared range and in a visible range thus emitted
Implementation Method 6
avalanche photodiode usage, confining and amplifying near-infrared and visible rays within the detector
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3
AI summary
Provided is an infrared detector comprising: a reflection portion (1) which transmits far- and middle-infrared rays and which reflects near-infrared and visible rays; a photo-current generating portion (2) having a quantum well structure in which electrons are excited by the far- and middle-infrared rays having passed through the reflection portion (1) so as to generate photo-current; a light emitting portion (3) having a quantum well structure into which electrons of the photo-current generated by the photo-current generating portion (2) are injected and in which the electrons thus injected thereinto are recombined with holes so as to emit near-infrared and visible rays; and a photo-detecting portion (4) which detects the near-infrared and visible rays emitted from the light emitting portion (3) and which detects the near-infrared and visible rays emitted from the light emitting portion (3) and reflected by the reflection portion (1). The reflection portion (1), the photo-current generating portion (2), and the light emitting portion (3) are made of group III-V compound semiconductors that are layered on top of a semiconductor substrate (10).