p型 (PbTe) の高ZT1-2x(PbSe) x(PbS) x熱電性材料について
Rachel J Korkosz1, Thomas C Chasapis, Shih-han Lo
1Department of Chemistry, and ‡Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
Journal of the American Chemical Society
|February 19, 2014
まとめ
この研究では,鉛カルコゲニドの新型熱電材料 (PbTe) 1−2x (PbSe) x (PbS) xを導入し,800 Kで約2.0のメリット数 (ZT) を得ています.この材料は帯域構造の変更と熱伝導性の低下により熱電性能を向上させています.
科学分野:
- 材料科学 材料科学とは
- 固体物理 固体物理学
- 熱電学は熱電学である.
背景:
- 鉛カルコゲニド熱電器は,帯状構造の修正またはナノ構造化によって高性能を達成します.
- (PbTe) 1-x(PbSe) xと (PbTe) 1-x(PbS) xに関する以前の研究では,それぞれ高い功率因数と低い熱伝導性が示されました.
研究 の 目的:
- 擬似二次性2%ナドーピング (PbTe) 1−2x(PbSe) x(PbS) xシステムの熱電特性について調査する.
- このシステムにおける固体溶液の振る舞いと相分離の相相競争を探求する.
- このシステムは,バイナリ対称と比較して優れた熱電気性能を提供しているか判断する.
主な方法:
- 擬似二次性2%のNa-ドーピング (PbTe)1-2x(PbSe)x(PbS)xシステムの合成と特徴付け.
- 電力因子と熱伝導率を含む熱電特性測定.
- バンド構造の変化と分散機構の分析.
主要な成果:
- 2%のNa-ドーピング (PbTe)1-2x(PbSe)x(PbS)xシステムは800Kで約2.0のメリット (ZT) を達成した.
- 2%のNa-ドーピングされたPbTe-PbSeとPbTe-PbSのバイナリシステムと比較して,優れた熱電特性が見られた.
- 600〜800Kの電気伝導性と熱力の高原は27μW/cmKの功率因子をもたらした.
- 低格子熱伝導率 (1.1 W/m·K for x=0.07) は,固体溶液の欠陥によるフォノン散乱に起因した.
結論:
- 擬三極 (PbTe) 1-2x(PbSe) x(PbS) xシステムは,高性能熱電応用のための有望な材料を表しています.
- バンド構造の変更と効果的なフォノン散乱は,メリットの熱電図の強化に寄与する.
- 材料の性能は,ナノ構造ではなく,固有の特性によって左右されます.
さらに関連する動画
関連する概念動画
P-N junction
1.7K
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
1.7K
Types of Semiconductors
1.8K
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
1.8K
Metal-Semiconductor Junctions
1.4K
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
1.4K
Biasing of Metal-Semiconductor Junctions
907
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
907
Biasing of P-N Junction
2.7K
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
2.7K
Zener Diodes
1.8K
Zener diodes are specialized semiconductor devices designed to operate in the reverse breakdown region, where they allow current to flow into the cathode, making it positive relative to the anode. This reverse operation distinguishes Zener diodes from conventional diodes and enables their use in various applications, most notably as voltage regulators. One of the defining characteristics of Zener diodes is their nearly vertical I-V (current-voltage) characteristic curve above a certain...
1.8K


