Self-assembly of ink molecules in dip-pen nanolithography: A diffusion model
Self-assembly of ink molecules in dip-pen nanolithography: A diffusion model
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DOI：
10.1063/1.1384550
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发表时间：
2001-08-08
影响因子：
4.4
通讯作者：
Ratner, MA
中科院分区：
文献类型：
--
作者：
Jang, JY;Hong, SH;Ratner, MA
利用浸笔式纳米光刻技术(DPN)沉积的墨水分子的自组装被模拟为具有源(尖端)的二维扩散。利用随机游走模拟和简单解析理论研究了扩散动力学对DPN中产生的模式的影响。对于产生恒定流量的墨水分子的喷嘴，通过改变墨水分子的沉积速率和喷嘴扫描速度来研究圆圈、线条和字母。即使在这里研究的最有利的条件下，由于自组装的随机、扩散性质，图案的外围也会从完美的圆形或线条波动。对圆和线的波动程度进行了量化。如果沉积相同数量的墨水，通过固定喷嘴位置产生的圆圈不依赖于沉积速率。对于移动的尖端，图案随尖端速度和沉积速率的不同而变化很大。总体而言，相对于扩散时间尺度的快扫描或慢沉积会使线更窄。当喷嘴沉积墨水太慢或扫描太快时，图案就会变得不连贯，使图案中的分子彼此分离。因此，沉积速度和尖端速度似乎有一个最佳的选择，可以同时提供窄的和相干的图案。我们还探讨了改变墨水分子在裸露表面和先前沉积的分子上的相对扩散速度的后果。(C)2001年美国物理研究所。
The self-assembly of ink molecules deposited using dip-pen nanolithography (DPN) is modeled as a two-dimensional diffusion with a source (tip). A random walk simulation and simple analytic theory are used to study how the diffusion dynamics affects patterns generated in DPN. For a tip generating a constant flux of ink molecules, circles, lines, and letters are studied by varying the deposition rate of ink molecules and the tip scan speed. Even under the most favorable condition studied here, peripheries of patterns fluctuate from perfect circles or lines, due to the random, diffusional nature of self-assembly. The degree of fluctuation is quantified for circles and lines. Circles generated by fixing the tip position do not depend on the deposition rate if the same amount of ink is deposited. For a moving tip, patterns change drastically depending on tip speed and deposition rate. Overall, fast scan or slow deposition relative to the diffusion time scale makes lines narrower. When the tip deposits ink too slowly or scans too fast, patterns become incoherent, making molecules in patterns separated from each other. Therefore, there seems to be an optimal choice of the deposition rate and tip speed that gives both narrow and coherent patterns. We also explore the consequences of varying the relative rates of diffusion of ink molecules on bare surface and on previously deposited molecules. (C) 2001 American Institute of Physics.