Fabrication via electrochemical oxidation of self-assembled monolayers and site-selective derivatization of surface templates
Fabrication via electrochemical oxidation of self-assembled monolayers and site-selective derivatization of surface templates
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DOI：
10.1002/smll.200500017
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发表时间：
2005-05-01
期刊：
影响因子：
13.3
通讯作者：
Schubert, US
中科院分区：
文献类型：
--
作者：
Hoeppener, S;Schubert, US
磁性材料在各个技术领域的技术影响推动了对不同材料磁性的持续研究。因此，诸如巨磁阻（GMR）效应[1，2]和隧穿磁阻[2]的新现象已经被发现，并且目前被集成到诸如磁性随机存取存储器（MRAM）器件的器件中[3]，并且将有助于磁性器件的进一步成功。随着结构化技术的改进，允许制造具有减小的器件尺寸的磁性结构，这种结构的附加特性变得可访问，并为新器件的有效构造提供了新的可能性。[4]即使是普通的磁性材料，在过去的几十年里，也取得了巨大的发展，以扩大和加速磁性数据存储容量，显着的经济效益是基于它们的快速发展。[5]因此，研究工作的关键任务是将单个存储位的大小限制降至最低。这被认为是基础和应用研究的关键问题。磁性的研究可以通过各种强大的技术进行;[6]特别是磁力显微镜（MFM）[7]有助于更好地理解磁性材料的性质。[8]这种技术允许高分辨率成像的磁性能，因此，甚至适合于调查的大小和形状对小的，纳米物体的磁性能的影响。[9]小的磁性纳米粒子可能提供许多新的可能性。除了这些颗粒的合成之外，还需要一种将它们以合适的、最优选有序的结构布置在表面上的方便方法。自发自组织可能只在某些系统中满足这一关键要求，因此有必要将联合收割机结构化技术和确定的纳米颗粒的组装结合起来。除了最先进的自上而下的结构化方法，它可以有效地用于产生结构下降到一定的尺寸限制，新开发的自下而上的光刻方法已经吸引了很大的兴趣，因为小的最终设备尺寸，可以潜在地实现。微接触印刷（μCP）[10]和最近的蘸笔纳米光刻（DPN）[11]为这种设计方法提供了合适的工具，并且已经展示了创建纳米尺寸磁性图案的第一个例子。[12]磁性结构也已经用在扫描力显微镜（SFM）图案化衬底上使用无电金属沉积的方法制造。[13]我们在这里报告的纳米图案化的自组装单层模板，这是由基于探针的电氧化纳米光刻产生的铁粒子的选址制造。通过向单层施加足够的电压，由于单层的表面封端甲基的氧化，引起表面功能的化学变化，[14，15]使单层的其余部分完全不受影响。这保持了单层的有用表面性质，例如疏水性、化学稳定性和机械坚固性。表面模板具有化学寻址能力，可用于自下而上的纳米纤维。不同的修改方案的引导组装的额外的材料在这样的表面图案，以及通过化学改性例程的表面模板的化学衍生化已经开发…
The technological impact of magnetic materials in various fields of technology has fueled sustained research into the magnetic properties of different materials. As a result, novel phenomena, such as for example, the giant magnetoresistance (GMR) effect [1, 2] and tunneling magnetoresistance [2] have been discovered and are currently integrated into devices, such as magnetic random access memory (MRAM) devices,[3] and will contribute to the further success of magnetic devices. With improving structuring techniques that allow the fabrication of magnetic structures with decreasing device dimensions additional properties of such structures become accessable and offer new possibilities for the effective construction of new devices.[4] Even with common magnetic materials, tremendous developments have been achieved to enlarge and speed-up magnetic data-storage capacities in the last decades and significant economical benefits are based on their rapid development.[5] Therefore research efforts address crucially the task of pushing the size limits of individual storage bits to a minimum. This is regarded as a key issue for fundamental and applied research. The investigation of magnetic properties can be performed by a variety of powerful techniques;[6] in particular, magnetic force microscopy (MFM)[7] has contributed to a better understanding of the properties of magnetic materials.[8] This technique allows the high-resolution imaging of the magnetic properties and is therefore suitable even for the investigation of size and shape effects on the magnetic properties of small, nanodimensional objects.[9] Small magnetic nanoparticles might provide many new possibilities. Besides the synthesis of these particles, a convenient way to arrange them in a suitable, most preferably ordered, structure on a surface is also desired. Spontaneous self-organization might fulfill this key requirement only in certain systems and therefore it is necessary to combine structuring techniques and the assembly of defined nanoparticles. Besides the state-of-the-art top-down structuring approaches, which can be efficiently utilized to generate structures down to a certain size limitation, newly developed bottom-up lithography approaches have attracted much interest because of the small ultimate device dimensions that can potentially be achieved. Microcontact printing (μCP)[10] and more recently also dip-pen nanolithography (DPN)[11] have provided suitable tools for this design approach and the first examples of creating magnetic patterns with nanometer dimension have been demonstrated.[12] Magnetic structures have also been fabricated with an approach that uses electroless metal deposition on scanning force microscopy (SFM) patterned substrates.[13] We report here on the site-selective fabrication of Fe particles on nanopatterned self-assembled monolayer templates, which are generated by probe-based electrooxidative nanolithography. By applying a sufficient voltage to the monolayer, a chemical change in the surface functions is induced due to the oxidation of the surface-terminated methyl groups of the monolayer,[14, 15] leaving the remaining part of the monolayer completely unaffected. This maintains the useful surface properties of the monolayer, such as hydrophobicity, chemical stability, and mechanical robustness. The surface templates exemplify a chemical addressability that can be used in terms of bottom-up nanofabrication. Different modification schemes for the guided assembly of additional material on such surface patterns, as well as the chemical derivatization of the surface templates by means of chemical modification routines have been developed …