Scanning Probe Microscopy development and applications for time resolved structure-function studies

原子力显微镜(AFM)是纳米科学和纳米技术的理想实验平台。它允许对单个纳米大小的物体进行成像、操作和表征。在过去的五年里，我的研究重点是开发测量纳米级系统电子性质的方法。一个特别的目标是发展时间分辨测量能力。我们已经成功地发展了原子力显微镜技术，利用静电针尖-样品相互作用，通过空间和时间分辨的原子力显微镜光谱方法来确定性质。我们通过原子力显微镜分辨100fS的非线性光信号，获得了有史以来最快的时间分辨率。另一项主要成果是用原子力显微镜测量了单个分子上的电子转移过程，使我们能够确定电子-声子耦合、分子振动和重组能。在接下来的5年里，我的研究计划的目标是在最近取得的一些实验突破的基础上，对纳米系统的结构-功能关系有一个基本的了解。被研究的材料在可再生能源发电、信息存储或量子信息处理方面具有长期潜力。一个特别的重点将是调查缺陷和无序在感兴趣的过程的动力学上的作用。这一研究计划为高素质人才的培养提供了一个丰富的、跨学科的、世界级的环境，开发了新的工具和方法，解决了根本问题，具有重大的应用潜力。具体地说，我们计划使用我们的低温原子力显微镜来表征与量子信息相关的硅中单个掺杂原子的电荷和耦合能。这些努力将与伦敦大学学院的N·柯森教授合作。同样，我们将研究蛋白质中的电子转移，以了解生物电荷漏斗系统中详细的结构-功能关系，以阐明一般原理，作为设计高效氢气和发电材料的仿生努力的输入。为此，我们将与世界一流的理论家教授合作。H.Guo和K.Bevan。我们将开发空间分辨的非线性光学测量，使用原子力显微镜作为探测器来研究光与物质的相互作用，特别是在有机和二维系统中。我们想了解这些系统中的大小、有序和缺陷是如何决定电导率和光电性质的。通过用100飞秒的光脉冲泵浦样品，我们将产生激子，并最终产生自由电荷。利用抽运探测和非线性光学方法，用具有纳米级空间和超快时间分辨率的原子力显微镜来表征这些材料的性质。实现这一点将打开一个新的研究领域：研究单个结构的性质，而不是整体平均。

Atomic force microscopy (AFM) is an ideal experimental platform for nanoscience and nanotechnology. It allows the imaging, manipulation and characterization of individual nanometer sized objects. In the past five years the focus of my research was on developing methods to measure the electronic properties of nanoscale systems. A particular aim was to develop time resolved measurement capabilities. We have succeeded in advancing AFM techniques to allow the determination of properties via spatially and time resolved AFM spectroscopy methods using electrostatic tip-sample interactions. We achieved the fastest ever reported time resolution by resolving a 100fs non-linear optical signal by AFM. A further major achievement was the measurement of the electron transfer process on a single molecule by AFM, allowing us to determine electron-phonon coupling, molecular vibration and reorganization energies. In the next 5 years the goal of my research program is to build on some of the recently achieved experimental breakthroughs and gain a fundamental understanding of the structure-function relation of nanoscale systems. Materials to be investigated have a long term potential for renewable energy generation, information storage or quantum information processing. A particular focus will be to investigate the role of defects and disorder on the dynamics of the process of interest. This research program provides a rich, interdisciplinary and world-class environment for the training of highly qualified personnel, develops new instrumentation and methods, addresses fundamental questions and has major application potential. Specifically, we plan to use our cryogenic AFM to characterize the charging and coupling energies of individual dopant atoms in silicon, relevant in quantum information. These efforts will be in collaboration with Prof. N. Curson at University College London. Similarly, we will investigate electron transfer in proteins to understand the detailed structure-function relation in biological charge funnel systems to elucidate general principles as input to biomimetic efforts to engineer efficient hydrogen and electricity generating materials. For this, we will collaborate with world-class theorists Profs. H. Guo and K. Bevan. We will develop spatially resolved non-linear optical measurements using AFM as a detector to investigate light-matter interactions, specifically in organic and 2 dimensional systems. We want to understand how size, order and defects in these systems determines conductivity and opto-electronic properties. By pumping the sample with 100 fs optical pulses we will generate excitons and ultimately free charges. The properties of these will be characterized by AFM with nanometer spatial and ultrafast time resolution using pump-probe and non-linear optics methods. Achieving this will open a wide new field of inquiry: studying the properties of individual structures in contrast to ensemble averaging.