growth and structure determination of thin films for future electronic technologies

许多新兴或未来的技术依赖于材料的原子水平控制，而这些材料的优化反过来又需要对材料特性的原子水平理解。在与微电子相关的应用中尤其如此，其中关键器件的性能取决于材料、表面和界面在从单个原子层到亚微米尺度上的详细特性。在本课题中，我们将利用新获得的低温扫描隧道显微镜（STM），将我们之前对表面和薄膜原子结构的研究范围扩大到两个应用领域。******首先是研究与有机电子器件（如有机发光二极管）性能相关的分子界面。这些装置的性能可能取决于单个分子层生长的确切方式。一些差异归因于分子在这些边界处的相对取向，但这方面的证据仅在少数系统中得到证实。我们将研究一系列广泛的分子界面，部分由低温STM实现，这将在成像时限制分子在表面的运动，并且还将实现更可靠的光谱测量。我们还将把这项工作扩展到分子掺杂体系，这在最新一代有机电子器件中越来越多地使用。对这些接口结构的详细了解所提供的见解将导致更好的基本理解，并将使该技术得到进一步改进。******第二个领域是由于Rashba效应而表现出自旋敏感电子结构的表面和薄膜的研究，在自旋电子学中具有潜在的未来应用。重点将是探索生长薄膜的特性，其中重金属原子的周期性排列可以通过半导体衬底的表面重建而产生。这将提供更广泛的原子结构，而不是通过观察拓扑绝缘体的体端接表面或含有二维层状化合物的重金属表面。我们还将重点关注表面缺陷的影响，这对这些材料的未来应用至关重要。******将这两个领域的工作联系起来的是STM以原子分辨率提供的结构和光谱信息。通过与另外两个小组的密切合作，这些信息将在一种情况下导致更好的有机电子器件性能，在另一种情况下，开发具有自旋依赖特性的新材料，用于自旋电子学的未来应用。

Many emerging or future technologies depend on the atomic level control of materials, and the optimization of such materials requires, in turn, an atomic level understanding of the materials properties. This is particularly true in applications related to microelectronics, where critical device performance depends on the detailed properties of materials, surfaces, and interfaces on length scales from individual atomic layers up to the sub micron scale. In this proposal, we will take advantage of a newly acquired low temperature scanning tunneling microscope (STM) to broaden the scope of our previous research on the atomic structure of surfaces and thin films to two areas of application. ******The first is the study of molecular interfaces relevant to the performance of organic electronic devices such as organic light emitting diodes. The performance of these devices can depend on the exact manner in which individual layers of molecules are grown. Some of the differences have been attributed to the relative orientations of molecules at such boundaries, but evidence for this has been demonstrated in only a handful of systems. We will study a broad set of molecular interfaces, enabled in part by cryogenic STM which will restrict the motion of molecules on the surface while imaging, and will also enable more reliable spectroscopic measurements. We will also extend this work to molecular dopant systems, which are increasingly being used in the latest generation organic electronic devices. The insights provided by a detailed knowledge of the structure of these interfaces will lead to a better fundamental understanding, and will enable further improvements in this technology.******The second area is the study of surfaces and thin films that exhibit spin sensitive electronic structure due to the Rashba effect, with potential future applications in spintronics. The emphasis will be on probing the properties of grown thin films where periodic arrangements of heavy metal atoms can be created via surface reconstructions of semiconductor substrates. This will provide a wider variety of atomic structures than would be available by looking at either the bulk terminated surfaces of topological insulators, or the surfaces of heavy metal containing 2D layered compounds. We will also focus on the influence of defects on surfaces, which will be vital for the future applications of these materials. ******What links the work in both areas is the structural and spectroscopic information provided at atomic resolution by STM. Through close collaboration with two other groups, this information will lead in one case to better organic electronic device performance, and in the other, development of new materials with spin dependent properties for future applications in spintronics.