Acquisition of a Scanning ESCA Spectrometer: Probing the Interfaces of Bio-, Geo- and Nanomaterials

购买 ESCA 扫描光谱仪：探测生物、地质和纳米材料的界面

• 批准号: 0321240
• 负责人: Vicki Colvin
• 金额: $ 45万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0321240&HistoricalAwards=false
• 关键词: Acquisition; Scanning; ESCA; Spectrometer; Probing

This grant supports the acquisition of a scanning electron spectroscopy for chemical analysis (ESCA) instrument for interface characterization of bio- , geo- and nanomaterials at Rice University. ESCA, also known as x-ray photoemission spectroscopy (XPS), is a powerful and versatile method for evaluating the surfaces of complex materials. The characterization of material interfaces is an important activity in much of materials research; for bio-, geo- and nanomaterials it is essential for developing new materials and understanding their properties. It is intrinsically a surface technique sensitive only to the top several angstroms of a sample, but with the appropriate conditions can be used to probe depths up to 20 nanometers. Several projects require depth profiling of atomic concentrations at surfaces while others need information about the nature of chemical bonding at interfaces. Still others are interested in chemical mapping of interfaces at the tens of micron level. Nearly all participants must be able to measure the atomic composition of surfaces, and the ability to analyze multiple samples quickly and consistently is of particular value. ESCA can measure the relative amounts of carbon and nitrogen at a surface and can determine whether the carbon is graphitic or bound to nitrogen. ESCA works by bombarding surfaces with a controlled X-ray source and resolving the kinetic energy of the photoemitted electrons; these energies are then used to identify surface atoms and their chemical state. Both the relative amounts of atomic species at surfaces, as well as their chemical environment can be deduced from XPS data. Though samples are evaluated under vacuum conditions, the technique is flexible- conductive and non-conductive powders and thin films have been analyzed with this method. The specific system has a focused, intense x-ray source, leading to small spot sizes (10 microns and high x-ray flux. This feature speeds data collection and its large sample platforms allow for rapid analysis of multiple samples. The scanning capability also enables a wider range of surface chemical experiments, such as depth profiles of atomic composition near surfaces and chemical mapping at the tens of micron length scale. The acquisition of a scanning ESCA will be especially significant to student training and development, specialized courses for undergraduates and graduates, and workshops. Over thirty graduate students, and tens of post-docs and undergraduates will be able to use this system to understand how surface chemistry plays a role in their research. The existence of a scanning ESCA will allow us to implement a set of programs that not only teaches students how to use the instrument, but also highlights the importance of interface chemistry in areas such as bio- and nanoengineering.

该赠款支持在赖斯大学（Rice University）的界面表征化学分析扫描电子光谱（ESCA）仪器。 ESCA，也称为X射线光发射光谱（XPS），是一种用于评估复杂材料表面的功能强大的方法。 材料界面的表征是许多材料研究中的重要活动。对于生物，地理和纳米材料，对于开发新材料和理解其特性至关重要。 从本质上讲，它仅对样品的顶部几个埃根敏感，但是在适当的条件下，可以用于探测高达20纳米的深度。 几个项目需要在表面上对原子浓度进行深度分析，而另一些项目则需要有关界面化学键合的性质的信息。还有一些人对在数十微米水平的界面进行化学映射感兴趣。几乎所有参与者都必须能够测量表面的原子成分，并且能够快速，一致地分析多个样品的能力特别有价值。 ESCA可以在表面上测量碳和氮的相对量，并可以确定碳是石墨还是与氮结合。 ESCA通过用受控的X射线源轰击表面并解决光电电子的动能。然后，这些能量用于鉴定表面原子及其化学状态。 可以从XPS数据中推导出表面上原子物种的相对量及其化学环境。 尽管在真空条件下对样品进行了评估，但该技术是柔性的，并且已通过这种方法分析了薄膜。特定系统具有集中，强烈的X射线源，导致小点尺寸（10微米和高X射线通量。此功能速度数据收集及其大型样本平台可快速分析多个样品。扫描能力也启用更广泛的表面化学实验，例如在表面附近的原子组成的深度谱以及在数十个微米长度尺度上的化学映射。毕业生和30名毕业生以及数十名后的学生和本科生将能够使用该系统来了解表面化学在其研究中如何发挥作用。不仅教学生如何使用该乐器的计划，而且还强调了在生物工程等领域的界面化学的重要性。