Computational investigations of the structure and properties of nanostructured materials

在纳米技术中，通过设计以预定方式组装并实现所需复合物或装置的制造组件，可以有效地实现朝向分子尺度的装置的小型化。纳米级晶体管阵列可以在纳米级上使用原子层沉积到高度共形的无机电介质和半导体薄膜的栅极导体上来制造。工作原型晶体管可以通过有机硅和半导体的自组装来制造，未来可能应用于制造更小，更强大的计算机芯片，用于电荷存储和机器人应用。嵌段共聚物被设计成自组装成具有设计性能的功能材料。自下而上的沉积和自组装工艺被预测为制造太阳能电池、传感器以及用于体内诊断和治疗的可行方法。 尽管最近取得了重大进展，但目前对分子和原子沉积过程以及在气体-表面界面发生的化学反应的理解仍然主要是经验性的和零碎的。理论研究可以提供有价值的洞察力，了解众多相关因素如何相互作用和影响这些过程。然而，在将系统作为一个整体来考虑时，考虑到当地相互作用的方法仍有待开发。总的来说，当前的计算研究要么解释实验数据，如基于经验初始结构的模拟，忽略局部相互作用，以粗粒度的方式对待整个系统，要么专注于长距离一致性使局部相互作用不重要的材料。我们感兴趣的纳米结构材料的问题是一个层次的规模的结果，我们的研究计划的目标，从长远来看，开发多尺度的方法来调查他们。这涉及一系列步骤：发展对局部分子水平行为的理解，然后将这种理解用于整体宏观系统的处理，最后将整体反馈提供给局部计算。在短期内，我们将集中在三个具有重大实际意义的现象：（a）原子层沉积过程的金属氧化物表面的沉积，重点是催化，替代和复杂的相互作用。(b)纳米结构表面的形成，着眼于包装，晶格失配，复杂结构的基板和竞争的势能表面上的最小值。这些现象在纳米级器件、生物传感器和功能材料的制造中具有直接的应用。(c)纳米结构材料的光电性能，着眼于与电荷存储、光致发光和可调介电和光响应相关的应用。

In nanotechnology, miniaturization of devices towards the molecular scale can be efficiently achieved by designing fabrication components that assemble in predetermined ways and realize the desired complex or device. Nanoscale transistor arrays can be manufactured at the nanoscale using atomic layer deposition onto the gate conductor of highly conformal inorganic dielectric and semiconductor thin films. Working prototype transistors can be fabricated via self-assembly of organic dielectrics and semiconductors, with potential future application in the fabrication of smaller, more powerful computer chips, for charge storage and robotics applications. Block copolymers are designed to self-assemble into functional materials with designed properties. Bottom-up deposition and self-assembly processes are forecast as viable methods for fabrication of solar cells, sensors, and for in-vivo diagnosis and treatment. Despite significant recent advances, the current understanding of molecular and atomic deposition processes, and the chemical reactions taking place at the gas-surface interface, are still mainly empirical and fragmentary. Theoretical research can provide valuable insight into how a multitude of relevant factors interact and impact these processes. However, methodologies to account for local interactions when considering the system as a whole are still challenging to develop. By and large, current computational investigations either interpret experimental data, such as simulations based on empirical initial structures, neglect local interactions and treat the entire system in a coarse-grained fashion, or focus on materials where long range conformity makes local interactions unimportant. The nanostructured materials problems we are interested in are the result of a hierarchy of scales, and our research program aims, in the long run, to develop multi-scale approaches to investigate them. This involves a succession of steps: Developing an understanding of the local, molecular level behaviour, then using this understanding in the treatment of the macroscopic system as a whole, and finally providing feedback about the whole to the local calculations. In the short term, we will focus on three phenomena of significant practical importance: (a) Atomic layer deposition processes for the deposition of metals at oxide surfaces, with an emphasis on catalysis, substitution, and complex interactions. (b) Nanostructured surface formation, with an eye on packing, lattice mismatches, complex-structured substrate and competing minima on the potential energy surface. These phenomena have immediate applications for nanoscale devices, biosensors, and the fabrication of functional materials. (c) The optoelectronic properties of nanostructured materials, with an eye towards applications related to charge storage, photovoltaics and tunable dielectric and optical response.