Mg2SiSnGe P-Type Semiconductor Composition Control
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Solution Overview
Problem
The preparation of a single-phase p-type thermoelectric semiconductor using the quaternary system Mg2SiXSnYGeZ is challenging due to the complexity of considering four phase diagrams, making it difficult to manufacture a p-type semiconductor with improved thermoelectric performance.
Innovation Solution
A method involving a liquid-solid reaction of magnesium, silicon, and germanium to produce a p-type semiconductor represented by the chemical formula Mg2SiXSnYGeZ, where X+Y+Z=1, X>0, Y>0, and Z>0, with specific ranges for X, Y, and Z to ensure a single-phase p-type semiconductor is achieved through sintering, maintaining the anti-fluorite structure and avoiding hazardous lead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a quaternary system Mg2SiXSnYGeZ is used to improve thermoelectric performance, then thermoelectric performance is improved, but the complexity of considering four phase diagrams makes it difficult to manufacture a single-phase semiconductor
Solution Approach 1:
The patent applies parameter changes by establishing specific compositional ranges for X, Y, and Z in the quaternary system Mg2SiXSnYGeZ. The method defines precise boundaries: 0.05≤X≤0.40, 0.60≤Y≤0.95, and Z satisfying −1.00Y+1.00≥Z≥−1.00Y+0.75 (when 0.60≤Y≤0.90) or −2.00Y+1.90≥Z≥−1.00Y+0.75 (when 0.90≤Y≤0.95). These parameter constraints simplify the complex phase diagram considerations into manageable compositional windows that guarantee single-phase formation, thus resolving the contradiction between improved thermoelectric performance and manufacturing complexity.
2Adaptability or versatility
If Pb is included in the list of elements that can change the Si site to form an anti-fluorite structure, then the list of available elements is expanded, but Pb is excluded because it is a hazardous metal
Solution Approach 1:
The patent applies the extraction principle by removing the hazardous element Pb from the list of elements that can occupy the Si site in the anti-fluorite structure, while retaining the beneficial non-hazardous elements Si, Ge, and Sn. This selective extraction maintains the structural and functional requirements (anti-fluorite structure formation, p-type conduction) while eliminating the harmful aspect (toxicity of Pb), thus resolving the contradiction between element selection flexibility and hazardous metal content.
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 method allows for the easy manufacture of a p-type semiconductor with optimized thermoelectric properties, maintaining a single-phase anti-fluorite structure and enhancing thermoelectric performance by controlling the composition ranges of X, Y, and Z, thereby overcoming the complexity of the quaternary system.
Implementation Method 1
obtained through liquid-solid reaction of magnesium, silicon, tin, and germanium as raw materials
Implementation Method 2
involves sintering a compound represented by the following general chemical formula: Mg2SiXSnYGeZ
Data Source
AI summary
A manufacturing method for a p-type semiconductor formed by sintering a compound represented by the general chemical formula: Mg2SiXSnYGeZ (where X+Y+Z=1, X>0, and Y>0, Z>0). The p-type semiconductor has a composition in which X is in the range of 0.00<X≦0.25, and Z satisfies the relationship: −1.00X+0.40≧Z≧−2.00X+0.10, where Z>0.00, and Y is in the range of 0.60≦Y≦0.95, and Z satisfies either of the relationships: −1.00Y+1.00≧Z≧−1.00Y+0.75, where 0.60≦Y≦0.90 and Z>0.00, and −2.00Y+1.90≧Z≧−1.00Y+0.75, where 0.90≦Y≦0.95 and Z>0.00.