Phononic Nanowire Pixel for Thermal Isolation
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Solution Overview
Problem
Current photonic sensors face limitations in detectivity, responsivity, temperature range, speed, manufacturing cost, and cost of ownership, particularly in pixelated formats for imaging arrays, with a need for improved thermal isolation and sensitivity across a broad wavelength range.
Innovation Solution
A phononically-enhanced infrared imager pixel (PEIP) is developed, featuring a micro-platform supported by nanowires within a cavity, incorporating thermally-isolated photonic sensing structures, including thermal and pn junction sensors, with Peltier thermoelectric cooling for reduced noise and enhanced sensitivity across visible to millimeter wavelengths, utilizing type II superlattice phototransistors for efficient hole and electron flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photonic sensors are packaged with sophisticated thermal isolation, then detectivity and sensitivity are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs phononic nanowires with porous or structured interiors that scatter phonons (heat carriers) while maintaining mechanical support. This porous/structured approach provides superior thermal isolation compared to solid thermal packages, improving detectivity without proportionally increasing complexity.
Solution Approach 2:
The invention applies thermal isolation selectively at the sensor pixel level using phononic nanowires rather than requiring complex thermal packages for the entire sensor array. This localized approach improves detectivity while avoiding system-wide complexity increases.
2Measurement precision
If photonic sensors operate at reduced temperatures, then detectivity and signal-to-noise ratio are improved, but manufacturing cost and operational complexity increase
Solution Approach 1:
The patent extracts the cooling function from complex external cryogenic systems and implements it at the pixel level using Peltier thermoelectric elements integrated directly with each sensor pixel. This enables reduced temperature operation for improved signal-to-noise ratio while simplifying overall system manufacturing.
Solution Approach 2:
Each sensor pixel is equipped with its own Peltier thermoelectric element for active cooling, enabling self-regulated temperature control. This eliminates the need for complex external cryogenic infrastructure, reducing manufacturing cost while maintaining improved signal-to-noise ratio through reduced temperature operation.
3Measurement precision
If thermal isolation is enhanced for passive photonic sensing, then sensitivity is improved, but thermal response time and operational speed may be reduced
Solution Approach 1:
The patent uses thin phononic nanowire structures that provide effective thermal isolation while maintaining minimal thermal mass. This thin-film approach enhances sensitivity through thermal isolation without significantly increasing thermal response time, as the isolated sensor pixel has low heat capacity.
Solution Approach 2:
The invention implements active thermal management using Peltier elements that dynamically adjust the temperature of sensor pixels based on operational requirements. This dynamic control optimizes both sensitivity (through thermal isolation and cooling) and response time (by preventing excessive heat buildup).
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 PEIP achieves increased detectivity, responsivity, and operational temperature range, while reducing manufacturing costs and noise, providing effective thermal isolation and sensitivity across a broad wavelength range, enabling improved performance in photonic sensor applications.
Implementation Method 1
The phononic nanowires comprise a semiconductor layer wherein thermal conductivity is significantly reduced providing thermal isolation for the micro-platform
Implementation Method 2
Peltier thermoelectric cooling for reduced noise and enhanced sensitivity
Implementation Method 3
photonic sensing structures each provide a signal responsive to absorbed incident radiation
Implementation Method 4
pn junction sensor having sensitivity to hole-electrons currents created as the absorbed photonic radiation is absorbed
Implementation Method 5
utilizing type II superlattice phototransistors for efficient hole and electron flow control
Data Source
AI summary
An imager pixel comprising a micro-platform supported by phononic nanowires, the nanowires providing an extreme-level of thermal isolation from a surrounding substrate. The micro-platform in embodiments comprises thermal sensors sensitive to heat from absorbed incident longwave/shortwave photonic irradiation. In embodiments, the pixel photonic sensing structure comprises both a thermal sensor together with a separate photodiode/phototransistor/photogate for sensing RGB and NIR wavelengths. Some embodiments comprise a micro-platform with an integral Peltier thermoelectric element permitting in situ refrigeration to cryogenic temperatures.