二次元の金属二カルコゲニドにおける電子と穴の内在的移動を制限する要因は?
1Texas Materials Institute and Department of Mechanical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States.
Journal of the American Chemical Society
|September 25, 2018
まとめ
二次元 (2D) 金属二カルコゲン化物 (MX2) の内在のキャリアモビリティは,効果的質量ではなく,フォノン散乱によって制限されます. 2次元半導体候補を予測できる.
科学分野:
- 材料科学
- 凝縮物質物理学
- 半導体物理学
背景:
- 二次元 (2D) 金属二カルコゲン化物 (MX2) は,多様な用途を持つ有望な二次元半導体である.
- MX2の低電子/穴の移動性は,それらの技術的進歩を妨げています.
- モビリティの限界を理解することは,優れた2D半導体材料の発見に不可欠です.
研究 の 目的:
- 幅広い2D MX2素材の内在的なキャリアモビリティの制限を調査する.
- キャリアのモビリティを左右する重要な要因を特定し,既存の理論に挑戦する.
- 高移動性の2D半導体候補をスクリーニングするための実用的な記述器を開発する.
主な方法:
- 密度機能障害理論 (DFPT) が採用された.
- 電子-フォノン行列のワニエのインターポレーションが利用された.
- 様々なMX2材料の包括的な研究が行われました.
主要な成果:
- 内在のキャリアの移動は,ほとんどのMX2で縦方向光学 (LO) フォノン散乱,およびMoS2とWS2で縦方向音響 (LA) フォノン散乱によって制限されます.
- モビリティは効果的質量と相関せず,変形電位理論の予測に従わない.
- LOの散乱力はボーン効果電荷と相関し,極化作用を示している.
結論:
- 生まれの有効電荷は,高流動性の2D MX2半導体のスクリーニングのための信頼できる記述器として機能します.
- この研究は,2D半導体のキャリアモビリティを制御する基本的な要因を明らかにします.
- この発見は,高度な 2D 材料の合理的な設計と開発の道を開きます.
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