MRI: Acquisition of a Low Energy Electron Microscope

该项目将委托一种新的低能电子显微镜(LEEM)设计，这代表着商业仪器的重大进步，并将使理解半导体和金属薄膜和团簇生长的基本机制方面取得突破性进展。LEEM使用从超低能量(约0-10 eV)光束反射的电子的成像，通过一组高空间分辨率对比度模式来研究表面和近地表区域的结构。垂直于样品表面的空间分辨率为原子尺度，而在样品表面平面内的空间分辨率约为5 nm。UVA的这台仪器还将支持多种额外的成像和衍射模式，包括光电子显微镜(PEEM)、镜面电子显微镜(MEM)和低能电子衍射(LEED)。这将使仪器具有无与伦比的能力，可以实时研究薄膜表面和生长过程中的结构、化学和反应。该仪器将在超高真空样品腔区域配备一套原位沉积和表面修饰能力，并将与超高分辨率聚焦离子束(FIB)源相结合，用于局部形貌、结晶学和化学的纳米尺度修饰。该仪器的初步研究重点将包括以下基础研究：在有潜在纳米电子应用的图案化表面上生长半导体团簇；生长用于新型磁阻和自旋电子学应用的超薄金属层状结构和隧道结；用于低温化学气相沉积(CVD)生长的化学反应的光学加速；物质的不同固态(结晶、非晶态、纳米晶和准晶)在金属合金生长中的相互作用；由表面反应形成碳化物的机制；以及腐蚀的原子机制。该文书还将对弗吉尼亚大学及其他地区的研究和教育基础设施产生广泛影响。它将被整合到我们的本科和研究生课程中的几个现有和计划中的课程中，并将为一系列现有和计划中的表面科学和纳米技术课程提供一个关键组成部分，用于真实演示表面和薄膜上的纳米级和原子级机制。此外，与IBM的研究人员的密切合作将为这些项目提供密切的工业研究合作和前景。该项目将委托一种先进的新设计的低能电子显微镜(LEEM)。LEEM通过对从样品表面反射的极低能电子进行成像来运行，从而产生可以检测表面形貌中的原子变化的图像。该仪器将配备一个超高真空样品室，允许对样品表面进行原子控制，从而能够直接成像表面的原子过程，包括薄膜生长、化学反应和腐蚀机理。从本质上讲，它允许我们观察自然界组装和改变材料表面原子结构的基本过程。这对加强对许多具有根本和实际重要性的进程的理解具有广泛的影响。例如，我们的仪器的初步应用将是研究表面加速的化学反应，组装新的纳米电子结构，探索先进磁性设备的材料，设计新的超强磁性材料，以及腐蚀的基本机制。该仪器还将在我们的本科生和研究生教育计划中发挥关键作用。通过纳入几门现有的和计划中的课程，它将提供表面和薄膜生长过程中原子尺度机制的真实演示。该项目的另一个基石是与IBM的研究人员密切合作。

This project will commission a new low energy electron microscope (LEEM) design that represents a major advance in commercially available instrumentation, and that will enable break-through advances in understanding of fundamental mechanisms of semiconductor and metallic thin film and cluster growth. LEEM employs imaging of reflected electrons from an ultra-low energy (c. 0 - 10 eV) beam to study the structure of surfaces and near-surface regions through a set of high spatial resolution contrast modes. Spatial resolution perpendicular to the sample surface is at the atomic-scale, while in the plane of the sample surface it is about 5 nm. The instrument at UVa will also enable multiple additional imaging and diffraction modes, including photoemission electron microscopy (PEEM), mirror electron microscopy (MEM), and low energy electron diffraction diffraction (LEED). This will enable an instrument with unparalleled capabilities for real-time nanoscale studies of structure, chemistry and reactions at surfaces and during growth of thin epitaxial films. The instrument will be equipped with a set of in-situ deposition and surface modification capabilities in an ultra high vacuum sample chamber area, and will be combined with an ultra-high resolution focused ion beam (FIB) source for nanoscale modification of local topography, crystallography, and chemistry. The initial research foci of this instrument will include fundamental studies of: Epitaxial growth of semiconductor clusters upon patterned surfaces with potential nanoelectronic applications; Growth of ultra-thin metallic layered structures and tunneling junctions for novel magnetoresistive and spintronics applications; Optical acceleration of chemical reactions for low temperature chemical vapor deposition (CVD) growth; The interplay of different solid states of matter (crystalline, amorphous, nanocrystalline and quasicrystalline) in the growth of metallic alloys; Mechanisms of carbide formation by surface reaction; and Atomistic mechanisms of corrosion. The instrument will also have broad impact upon the research and educational infrastructure at UVa and beyond. It will be integrated into several existing and planned courses in our undergraduate and graduate curricula, and will provide a key component for real-life demonstrations of nano-scale and atomic-scale mechanisms on surfaces and thin films for a set of existing and planned courses in surface science and nanotechnology. In addition, a close collaboration with researchers at IBM will provide close industrial research collaborations and perspective for these programs.This project will commission a low energy electron microscope (LEEM) of an advanced new design. The LEEM operates by imaging of electrons of very low energy which have been reflected from a sample surface, thereby producing images which can detect atomic changes in topography on the surface. The instrument will be equipped with an ultra-high vacuum sample chamber to allow atomic control of sample surfaces, thereby enabling direct imaging of atomic processes at surfaces, including growth of thin films, chemical reactions, and corrosion mechanisms. In essence, it allows us to watch the fundamental processes by which nature assembles and modifies the atomic structure of the surfaces of materials. This has broad ramifications for enhanced understanding of many processes of fundamental and practical importance. For example, initial applications of our instrument will be studies of accelerated chemical reactions at surfaces, assembly of new nanoelectronic architectures, exploration of materials for advanced magnetic devices, design of new ultra-strong magnetic materials, and fundamental mechanisms of corrosion. The instrument will also play a key role in our undergraduate and graduate education programs. By incorporation into several existing and planned courses, it will provide real-life demonstrations of atomic-scale mechanisms on surfaces and during thin film growth. Another cornerstone of this project is close collaboration with researchers at IBM.