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.
