Field emission and anode etching during formation of length-controlled nanogaps in electrical breakdown of horizontally aligned single-walled carbon nanotubes
Field emission and anode etching during formation of length-controlled nanogaps in electrical breakdown of horizontally aligned single-walled carbon nanotubes
复制标题
水平排列单壁碳纳米管电击穿中长度控制纳米间隙形成过程中的场发射和阳极蚀刻
DOI：
10.1039/c6nr05449h
复制
发表时间：
2016
期刊：
影响因子：
6.7
通讯作者：
S. Maruyama
中科院分区：
文献类型：
--
作者：
K. Otsuka;T. Inoue;Y. Shimomura;S. Chiashi;S. Maruyama
我们观察了单壁碳纳米管（SWNTs）在电击穿过程中纳米间隙之间的场发射和电压驱动的间隙扩展。实验结果表明，间隙大小与施加的电压和湿度有关，表明间隙大小的可控性很高，可以根据应用情况适当调整这些参数。我们提出电击穿间隙形成的机制如下。在焦耳加热诱导氧化形成小间隙后，由于空气中物理吸附的水和SWNT尖端处增强的电场，阳极侧的SWNT被电化学蚀刻。在真空中测量场发射，作为SWNT间隙电荷转移的可能机制。场增强因子与单壁碳纳米管几何特性之间的关系既解释了扩展隙尺寸的电压依赖性，也解释了单壁碳纳米管隙的场发射特性。此外，类似的场致蚀刻会对相邻的单壁碳纳米管造成损伤，这可能会降低在水蒸气存在下切割金属通路的选择性。
We observe field emission between nanogaps and voltage-driven gap extension of single-walled carbon nanotubes (SWNTs) on substrates during the electrical breakdown process. Experimental results show that the gap size is dependent on the applied voltage and humidity, which indicates high controllability of the gap size by appropriate adjustment of these parameters in accordance with the application. We propose a mechanism for the gap formation during electrical breakdown as follows. After small gaps are formed by Joule heating-induced oxidation, SWNTs on the anode side are electrochemically etched due to physically-adsorbed water from the air and the enhanced electric field at the SWNT tips. Field emission is measured in a vacuum as a possible mechanism for charge transfer at SWNT gaps. The relationship between the field enhancement factor and geometric features of SWNTs explains both the voltage dependence of the extended gap size and the field emission properties of the SWNT gaps. In addition, the similar field-induced etching can cause damage to adjacent SWNTs, which possibly deteriorates the selectivity for cutting metallic pathways in the presence of water vapor.