Semiconductor Stacked Structure for Thermoelectric Conversion
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Solution Overview
Problem
Conventional thermoelectric conversion devices face challenges in achieving high conversion efficiencies due to the direct proportionality between electrical conductivity and thermal conductivity in semiconductor materials, making it difficult to enhance the figure of merit ZT, which is crucial for middle-range power applications.
Innovation Solution
A thermoelectric conversion device is designed with a semiconductor stacked structure composed of alternating layers of different semiconductor materials, such as InGaAlAs and InP, or InGaAsP and InGaAlAs, to avoid conduction or valence-band discontinuities, facilitating electron diffusion and phonon scattering, thereby increasing the figure of merit ZT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-material semiconductor components are used, then the device structure is simple, but the figure of merit ZT cannot be enhanced due to direct proportionality between electrical conductivity and thermal conductivity
Solution Approach 1:
The patent employs composite semiconductor materials with different band gaps (e.g., InGaAlAs and InP) arranged in a stacked structure. This composite approach allows independent optimization of electrical and thermal properties in different layers, breaking the direct proportionality between electrical conductivity and thermal conductivity that limits single-material systems, thereby enhancing the figure of merit ZT
2Reliability
If semiconductor layers with different materials are stacked, then the figure of merit ZT is enhanced, but conduction-band or valence-band discontinuity occurs
Solution Approach 1:
The patent carefully adjusts material composition parameters (such as indium, gallium, and aluminum content ratios) and layer thickness parameters to achieve continuous conduction and valence bands across interfaces. By precisely controlling these parameters, the design maintains high figure of merit ZT while eliminating band discontinuities that would impede carrier transport
3Productivity
If alternating semiconductor layers are used to facilitate electron diffusion and phonon scattering, then conversion efficiency is enhanced, but the device structure becomes more complex
Solution Approach 1:
The patent divides the semiconductor structure into multiple alternating layers with different materials (e.g., InGaAlAs and InP) stacked in sequence. This segmentation creates numerous interfaces that selectively scatter phonons while maintaining electron diffusion, thereby enhancing conversion efficiency. The modular layered design also facilitates systematic optimization of each layer's properties
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
This configuration significantly enhances the conversion efficiency of thermoelectric devices by optimizing electrical conductivity while reducing thermal conductivity, achieving higher ZT values that were previously difficult to attain with single-material systems.
Implementation Method 1
Thermoelectric conversion devices employing the Seebeck effect can recycle waste heat
Implementation Method 2
a material and a composition of each semiconductor layer in the semiconductor stacked structure are selected so as to avoid conduction-band or valence-band discontinuity
Implementation Method 3
semiconductor layers stacked with each other, the semiconductor layers being made from different semiconductor materials
Data Source
AI summary
In order to achieve a thermoelectric transducer exhibiting a higher conversion efficiency and an electronic apparatus including such a thermoelectric transducer, a thermoelectric conversion device is provided, including a semiconductor stacked structure including semiconductor layers stacked with each other, the semiconductor layers being made from different semiconductor materials, in which a material and a composition of each semiconductor layer in the semiconductor stacked structure are selected so as to avoid conduction-band or valence-band discontinuity.