Surface Analytical Chemistry with Intense Picosecond Laser Light

高灵敏度的固体表面分析， 动态范围对许多技术都很重要，包括 半导体加工和多相催化。本研究 由分析和表面化学计划，a 皮秒激光将用于直接在固体上方照射物质 表面，然后通过飞行时间质谱分析它们。 这些物质将通过离子束或激光束相互作用解吸， 分析表面。 该研究计划的目标是 为了开发这种表面分析方法， 光电离过程，测量速度和角分布， 溅射粒子，并通过确定检测灵敏度因子， 相对中性和离子分数溅射产率。 为了检测半导体表面上的低水平污染物， 或识别催化体系中的低覆盖度物种， 拥有非常灵敏的表面分析工具。 本研究 该计划旨在开发和完善一个非常敏感的 表面组成的光电离探针。 快速激光脉冲将 用于离子或激光解吸的物质，质谱法将 用于检测和识别离子。这种方法承诺， 表面分析灵敏度显著提高 可用的方法。

Analysis of solid surfaces with high sensitivity, and with a broad dynamic range, is important to a number of technologies, including semiconductor processing and heterogeneous catalysis. In this research project supported by the Analytical and Surface Chemistry Program, a picosecond laser will be used to ionize species directly above a solid surface, and then analyze them by time of flight mass spectrometry. These species will be desorbed by ion beam or laser beam interaction with the surface being analyzed. The objectives of this research program are to develop this surface analysis method by carefully characterizing the photoionization process, measuring velocity and angular distributions of sputtered particles, and by determining detection sensitivity factors and relative neutral and ion fraction sputtering yields. In order to detect low levels of contaminants on semiconductor surfaces, or to identify low coverage species in catalytic systems, it is necessary to have available very sensitive surface analytical tools. This research program is designed to develop and perfect a very sensitive photoionization probe of surface composition. A fast laser pulse will be used to ionize ion or laser desorbed species, and mass spectrometry will be used to detect and identify the ions. This approach promises a significant increase in surface analytical sensitivity over presently available methods.