Acquisition of an Ultrahigh Vacuum Scanning Tunneling Microscope for the Study of Surface Chemistry and Surface Physics

扫描隧道显微镜极大地拓宽了我们对半导体和金属的理解，提供了其他技术所不能提供的材料表面的独特视角。具体地说，显微镜分辨单个表面原子的能力使人们更好地理解了固体表面的化学和物理。化学反应如何在表面上进行，或者不同的表面原子如何扩散、分离或结合，都可以在原子尺度上进行观察。该获奖仪器将用于研究金属硅化物在硅上的形成，因为金属/半导体界面继续影响器件制造。在更基本的层面上，了解导致金属硅化物形成的过程将允许控制纳米级粒子的形成，这些粒子通过其反应性驱动自组装。该仪器还将被用来研究氮化镓(可以用来制造发射蓝/紫光的电光设备)上的反应过程。特别是，氮化镓表面上的氢的动力学是有技术意义的，也可以用来作为局部表面反应性的探针。由于氮化镓表面也是极性的(N端与Ga端)，因此也将研究表面极性对表面反应的影响。半导体被广泛应用于电子和电光器件。例如，几乎所有的计算机芯片都是由硅制成的。化合物半导体(所谓的III-V半导体)经常出现在将电能转换为光的设备中，即发光二极管和激光二极管，发光二极管几乎在所有消费电子产品中都有，激光二极管构成了固态激光器的核心，激光打印机和光盘播放机的引擎。对半导体的研究导致了更快、更小的计算机芯片(因此也就是计算机)和新型电光设备的发展。扫描隧道显微镜极大地拓宽了我们对半导体和金属的了解，提供了任何其他技术所不能提供的材料表面的独特视角。具体地说，这种显微镜能够获得表面的原子分辨率图像。有了它，表面物理和化学就可以在原子尺度上观察到。简而言之，原子如何在表面上运动和分布，或者化学反应如何在表面上进行，可以直接用扫描隧道显微镜来成像。获奖仪器将用于加深我们对金属与硅相互作用的理解，并研究用于电光应用的新型半导体材料的表面化学。

0079796McEllistremThe scanning tunneling microscope has done much to broaden our understanding ofSemiconductors and metals, providing a unique view of material surfaces available by noother technique. Specifically, the microscope's ability to resolve individual surfaceatoms has lead to an improved understanding of the chemistry and physics of solidsurfaces. How a chemical reaction proceeds on a surface, or how different surface atomsdiffuse, segregate, or combine can be literally watched on an atomic scale. The awardedinstrument will be used to investigate the formation of metal silicides on silicon, sincemetal/semiconductor interfaces continue to impact device fabrication. At a morefundamental level, understanding the processes that lead to metal silicide formation willallow the controlled formation of nanoscale particles, particles that are driven to self-assembleby their reactivity. The instrument will also be used to investigate how reactions proceed on gallium nitride (from which electro-optic devices that emit in the blue/violet can be made). In particular, the dynamics of hydrogen on the gallium nitride surface is of technological interest, and can also be used as a probe of local surface reactivity. Since gallium nitride surfaces are also polar (N- vs. Ga-terminated), the impact of surface polarity on surface reactions will also be studied.Semiconductors are widely used in electronic and electro-optic devices. Nearly allcomputer chips, for example, are fabricated from silicon. Compound semiconductors(the so-called III-V semiconductors) are often found in devices which convert electricalenergy into light, namely light-emitting diodes, found in nearly all consumer electronics,and laser diodes, which form the heart of a solid state laser, the engine in laser printers and compact disc players. Research into semiconductors has lead to the development of faster, smaller computer chips (and thus computers), and novel electro-optic devices. The scanning tunneling microscope has done much to broaden our knowledge of semiconductors and metals, providing a unique view of material surfaces unavailable by any other technique. Specifically, this microscope is capable of attaining atomic resolution images of surfaces. With it, surface physics and chemistry can observed on an atomic scale. In short, how atoms move and distribute themselves on a surface, or how a chemical reaction proceeds on a surface, can be imaged directly with a scanning tunneling microscope. The awarded instrument will be used to further our understanding of how metals interact with silicon, and to investigate the surface chemistry of novel semiconductor materials used in electro-optic applications.