Assembly of nanoelectronic device-structures on lithium niobate templates by means of Ferroelectric Lithography

当代纳米技术的一个核心挑战是通过采用具有成本效益的自下而上的方法以可重复和并行的方式生产功能性纳米器件。为了实现这一目标，铁电模板非常适合，允许通过称为“铁电光刻”（FE-Litho）的方法进行受控的纳米结构自组装。在FE-Litho中，铁电畴图案将您选择的纳米结构沉积到铁电（FE）模板上。由于FE域可以在从纳米到厘米的宽尺寸范围内以高精度任意图案化，因此FE-Litho不仅适用于这种自下而上的纳米工程，而且在集成和功能方面出色地将纳米世界与宏观世界联系起来。（LiNbO 3，LNO）非常适合作为我们选择的FE模板，因为来自液相的任何物质的光化学沉积仅限于吸附到铁电畴壁（DW）。此外，LNO中的这些180° DW的宽度小于10 nm，因此将沉积限制在明确定义的纳米空间内。因此，本项目的第一个目标是利用这种具有挑战性的FE光刻技术，通过使用碳纳米管（CNT），生物DNA分子，和贵金属纳米线作为构建块。我们的第二个目标是彻底的和基本的调查，导致这种DW装饰过程中的LNO表面的物理和化学的驱动力，这至今仍不清楚。为了实现这些目标，我们计划建立一个原位和全自动FE-光刻组装平台的基础上，包括一个扫描力显微镜（AFM）安装在倒置的紫外光学显微镜顶部的液体流动池。然后使用该设置来完成所有的制备步骤（例如，UV诱导的域工程、光化学DW装饰、CNT分选和层流下的沉积），以及使用先进的AFM模式（例如，导电AFM、压电响应和开尔文探针力显微镜）来执行原位表征。

A central challenge for contemporary nanotechnology is the production of functional nanodevices in a reproducible and parallel way by employing cost-efficient bottom-up methods. In order to accomplish this goal, ferroelectric templates are well suited, allowing for the controlled nanostructure self-assembly by the method known as "Ferroelectric Lithography" (FE-Litho).In FE-Litho, ferroelectric domain patterns direct the deposition of the nanostructures of your choice to the ferroelectric (FE) template. Since FE domains can be arbitrarily patterned with high accuracy over a broad size-range from nanometers to centimeters, FE-Litho not only is applicable for this bottom-up nano-engineering but, furthermore, excellently bridges the nano- to the macroscopic world with respect to integration and functionality.Lithium niobate (LiNbO3, LNO) is well suited as the FE template of our choice, since photochemical deposition of any species from the liquid phase is confined to adsorption to the ferroelectric domain wall (DW), only. Moreover, these 180° DWs in LNO measure less than 10 nm in width thus confining the deposition to a clearly defined nano-space.The first goal of this project hence is to make use of this challenging FE-Litho technique in order to build-up functional nanodevices, e.g. field effect transistors, bio assays, and coaxial nanocables, by employing carbon nanotubes (CNT), biological DNA molecules, and noble-metal nanowires as the building blocks, respectively. Our second goal is the thorough and fundamental investigation of the physical and chemical driving forces leading to this DW decoration process on LNO surfaces, which to date is still unclear.To achieve these aims, we plan to set up an in-situ and fully automated FE-Litho assembly platform based on a liquid-flow-cell including a scanning force microscope (AFM) mounted on top of an inverted UV-optical microscope. This setup then is used to accomplish all the preparation steps (e.g. UV-induced domain engineering, photochemical DW decoration, CNT sorting and deposition under laminar flow) as well as to perform the in-situ characterization using advanced AFM modes such as conductive AFM, piezo-response and Kelvin probe force microscopy.