Scanning Probe Microscopy for fundamental studies in nanoscience

原子力显微镜(AFM)是纳米科学的理想工具，因为它允许对单个纳米尺寸的物体进行成像、操作和表征。我的研究计划的长期目标是通过建立在NSERC DG资助的最新实验突破和仪器开发的基础上，继续从根本上了解纳米级系统在信息存储或处理方面的结构-性质关系。这一研究计划为HQP和许多潜在的社会经济技术衍生产品的培训提供了一个丰富的、跨学科的和世界级的环境。 我们计划使用我们的两个独特的超高真空原子力显微镜系统，了解单分子器件的电导和机械性能，这可能成为未来纳米电子学的基础。我们想了解分子电子学中的问题：接触的作用。目前可用的实验数据与理论模型的比较是非常困难的，因为接触导线的原子结构是至关重要的，但通常不是实验控制的。 另一个项目是了解有机分子系统中的有序和缺陷是如何决定电导率和光电性质的。通过用~100fs的光脉冲泵浦样品，我们将产生激子，并最终产生自由电荷。通过检测原子力显微镜针尖上产生的静电力，我们将获得纳米级的空间分辨率。因此，我们将与光学和太赫兹光谱学专家合作，对有机系统中的光-物质相互作用、电荷分离和导电性有深入的了解。 我们计划使用我们的低温原子力显微镜来表征半导体和金属量子点(QD)的电荷。我们对机械探测到的单电子信号的详细定量理解使我们能够提取单个量子点和耦合量子点的能级、态密度以及耦合强度。我们将测试一个令人兴奋的理论预测，即相干时间T1可以直接从我们的AFM耗散测量中提取！我们还旨在观察由于单个分子耦合到量子点而引起的电荷转移，从而导致实验上可观察到的能级和能级排列的移动。通过改变偶联化学，这将导致对有机接触的详细理解。 最后，我们将继续努力从根本上了解生物系统是如何处理信息的。我们特别感兴趣的是了解是什么决定了神经元的信号处理能力。我们最近证明，我们可以构建新的、功能正常的神经元连接。因此，我们现在可以通过实验控制所有相关参数，以了解简单的生物神经网络，以期实现在工程纳米电子系统中学到的经验教训。

The atomic force microscope (AFM) is an ideal tool for Nanoscience, as it allows imaging, manipulation and characterization of individual nanometer sized objects. The long-term aim of my research program is to continue to gain a fundamental understanding of the structure-property relation of nanoscale systems with respect to information storage or processing by building on recent NSERC DG funded experimental breakthroughs and instrumentation developments. This research program provides a rich, interdisciplinary and world-class environment for the training of HQP and many potential socio-economic technology spin-offs. We are planning on understanding the conductance and the mechanical properties of single molecular devices that could form the basis of future nanoelectronics using our two unique UHV AFM systems. We want to understand THE issue in molecular electronics: the role of contacts. The comparison of currently available experimental data with theoretical modeling is very difficult, as the atomic structure of the contact leads is of utmost importance, but usually not experimentally controlled. A further project is to understand how order and defects in organic molecular systems determines conductivity and opto-electronic properties. By pumping the sample with ~100 fs optical pulses we will generate excitons and ultimately free charges. By detecting the resulting electrostatic forces on the AFM tip we will achieve nm scale spatial resolution. In collaboration with specialists in optical and THz spectroscopy we will thus gain a deep understanding of light-matter interactions, charge separation and conductivity in organic systems. We plan to use our cryogenic AFM to characterize the charging of semi-conducting and metallic quantum dots (QD). Our detailed quantitative understanding of the mechanically detected single electron signals allows us to extract the energy levels, density of states as well as coupling strengths of individual and coupled QD. We will test an exciting theoretical prediction that the coherence time T1 can be directly extracted from our AFM dissipation measurement! We also aim to observe the charge transfer due to a single molecule coupled to a QD, resulting in a shift of the experimentally observable energy levels and energy level alignment. By changing the coupling chemistry this will lead to a detailed understanding of organic contacts. Finally, we will continue our efforts to fundamentally understand how biological systems process information. We are in particular interested in understanding what determines the signal processing capabilities in neurons. We recently demonstrated that we could construct new, functioning neuronal connections. We can thus now experimentally control all the relevant parameters to understand a simple biological neuronal network with a view of implementing the lessons learned in engineered nanoelectronics systems.