金属碳纳米管接触:斯科特基屏障和化学结合之间的联系
Vincenzo Vitale1, Alessandro Curioni, Wanda Andreoni
1IBM Research, Zurich Research Laboratory, 8803 Rüschlikon, Switzerland.
Journal of the American Chemical Society
|April 16, 2008
概括
了解碳纳米管 (CNT) 场效应晶体管中的肖特基屏障高度 (SBH) 是先进电子学的关键. 在金属接触处的化学粘合,而不仅仅是金属类型或几何,决定了SBH,从而实现了更好的接触设计.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 纳米技术纳米技术
背景情况:
- 碳纳米管 (CNT) 场效应晶体管 (FET) 对CMOS后微电子有希望.
- 在金属源接触处的Schottky屏障 (SB) 显著影响CNT运输.
- 连接金属-CNT接口属性与Schottky屏障高度 (SBH) 的确切机制尚不清楚.
研究的目的:
- 阐明金属-CNT接口上的化学结合与SBH之间的关系.
- 为了研究金属类型 (Al,Pd) 和接触几何 (末端,侧面) 对SBH的影响.
- 为 CNT 设备设计改进的金属接触器提供见解.
主要方法:
- 密度函数理论 (DFT) 的计算被广泛执行.
- 模拟涵盖了端和侧接触几何.
- 分析了两个不同的金属, (Al) 和 (Pd).
主要成果:
- 确定了化学键性质和SBH之间的直接相关性.
- 孔的低SBH与保存的CNT pi电子系统与金属原子的结合有关.
- 增强的SBH来自金属状态与CNT西格玛系统或pi系统扰动 (sp3杂交) 的合.
结论:
- 金属-CNT接口的化学成分从根本上决定了SBH.
- 由于有利的粘合,Pd接触在两种几何形状中都表现出低的SBH.
- 阿尔侧接触显示低SBH,而阿尔端接触由于结合扰动而具有高SBH.
- 这些发现使得CNT电子器件的"良好的接触"能够合理设计.
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