Positron Annihilation Induced Auger Spectroscopy

9812628 Weiss在这个项目中，PI希望利用他发明的光致俄歇电子能谱（PAES）技术，将其扩展到三个新的实验方面。 与传统的俄歇电子能谱（AES）相比，PAES方法可以非破坏性和选择性地探测材料的最顶层原子层。 产生的PAES光谱也不受使常规俄歇光谱复杂化的大的二次电子背景的影响。 PAES方法已被证明是俄歇光谱学领域的一个重大进展，现在正在许多实验室中引入。 在拟议的工作中，PI不仅将继续进行已经进行的调查，而且还将攻击半导体衬底上的金属和半导体超薄膜的生长和稳定性问题，模型多组分非均相催化剂顶层的元素组成问题，以及NiAl合金顶层的表面偏析问题。 PAES的主要新的应用将针对半导体中的缺陷的研究和正电子湮没与核心电子的基础研究，特别注意在GaAs，InP，Si和CdTe中的带电缺陷和空位杂质复合物的识别。此外，PI建议使用PAES湮灭伽马符合实验来测量，第一次，多普勒展宽湮没伽马光谱与个人核心水平。将通过完成高效飞行时间PAES光谱仪和开发高效场辅助正电子减速器来升级实验设施。 这些活动和其他活动将与研究生和博士后研究人员一起进行，他们将因此接受对21世纪工业技术非常重要的实验物理领域的培训。在这个项目中，首席研究员将扩大他发明的一种新技术的应用，用于研究固体材料和沉积在其上的超薄膜的性质。 这种技术称为光致俄歇电子能谱，与传统使用的俄歇电子能谱相比具有重大优势，目前已被美国和其他国家的许多实验室引入。 本提案提出了一个丰富多样的研究计划，包括通过建造辅助设备来扩展该技术。 研究生和博士后研究人员将在实验物理领域接受良好的培训，这对21世纪世纪的工业技术具有重要意义。 ***

9812628WeissIn this project the PI wishes to capitalize on his invention of the technique of Photoinduced Auger Electron Spectroscopy (PAES) by extending it to incorporate three novel experimental aspects. Compared to conventional Auger Electron Spectroscopy (AES) the PAES method probes the top most atomic layers of materials non-destructively and selectively. The PAES spectra that are produced are also free from the large secondary electron background that complicates conventional Auger spectroscopy. The PAES method has proven to be a major advance in the filed of Auger spectroscopy and is now being introduced in many laboratories. In the proposed work the PI will not only continue the investigations already underway but also attack the problems of the growth and stability of ultra thin films of metals and semiconductors on semiconductor substrates, of the elemental composition of the top layer in model multi-component heterogeneous catalysts, and of surface segregation to the top layer in NiAl alloys. Major new applications of PAES will be directed to the studies of defects in semiconductors and to fundamental studies of positron annihilation with core electrons, with specific attention given to the identification of charged defects and vacancy impurity complexes in GaAs, InP, Si, and CdTe. Additionally, the PI proposes to use PAES-annihilation-gamma coincidence experiments to measure, for the first time, the Doppler broadened annihilation gamma spectra associated with an individual core level. The experimental facilities will be upgraded through the completion of a highly efficient time-of-flight PAES spectrometer and the development of highly efficient field assisted positron moderators. These, and other activities, will be carried out with graduate students and post doctoral research associates who will thereby receive training in an area of experimental physics that is of great importance to industrial technology in the 21st Century.%%%In this project the principal investigator will extend the application of his invention of a new technique for studying the properties of solid materials and ultra thin films deposited on them. This technique, called Photoinduced Auger Electron Spectroscopy, has major advantages over the conventionally used Auger Electron Spectroscopy and is now introduced in many laboratories in the USA as well as in other countries. The present proposal presents a rich and varied research program, including the extension of the technique through the construction of ancillary apparatus. Graduate students and post doctoral research associates will receive excellent training in an area of experimental physics that is of importance to the industrial technology of the 21st Century. ***