Acquisition of an Infrared Ellipsometer for Materials Research and Student Training

该补助金为亚利桑那州立大学的材料研究和学生培训提供了红外光谱椭偏仪的购买支持。 该仪器将配备一个低温恒温器附件，允许可变温度操作。这种能力极为罕见：新仪器将是美国制造的第一台此类仪器。光谱椭偏仪测量作为波长的函数的材料的折射率的真实的部分和虚部。在光谱的红外范围内，主要的光学激发是掺杂材料中的声子（振动）、等离子体激元（集体电子振荡）和窄隙半导体中的带间电子激发。因此，新的椭偏仪将在氧化物、铁电材料和半导体的表征中发挥关键作用，这是亚利桑那州立大学积极研究的领域，也是工业合作伙伴非常感兴趣的领域。椭偏光谱法比光透射或反射实验具有显著的优点。后者测量每个波长的单个量（透射或反射光的强度），而椭圆偏振测量在表面反射的光的偏振变化。由于这种变化的特征在于振幅比和相移（与平面内偏振的光的反射系数有关，并且垂直于入射平面），因此椭圆偏振法具有高度准确性和可再现性，即使对于低光水平也是如此。此外，它不需要参考样品，受样品光散射的影响较小，并且可以用于确定光学常数的绝对值而无需独立的厚度测量。预计该项目将产生广泛的社会影响。其独特的方面之一将是ASU与工业合作者之间的协同合作，这些合作者在ASU人员的培训中发挥着关键作用。将特别强调促进科学教育。要求提供资金，以支持仪器在第一年的运作，这些资金将主要用于培训学生。工业合作者将在这些活动中发挥关键作用，监督学生，提供样品，并教授椭圆偏振短期课程。

This grant provides support for the acquisition of an infrared spectroscopic ellipsometer for materials research and student training at Arizona State University. The instrument will be equipped with a cryostat attachment allowing variable temperature operation. Such capability is extremely rare: the new instrument will be the first of its kind manufactured in the United States. A spectroscopic ellipsometer measures the real and imaginary parts of a material's index of refraction as a function of wavelength. In the infrared range of the spectrum, the dominant optical excitations are phonons (vibrations), plasmons (collective electronic oscillations) in doped materials, and band-to-band electronic excitations in narrow gap semiconductors. Accordingly, the new ellipsometer will play a key role in the characterization of oxides, ferroelectric materials, and semiconductors, areas of active research at Arizona State University and of great interest to industrial partners. Spectroscopic ellipsometry has significant advantages over light transmission or reflection experiments. The latter measure a single quantity at each wavelength (the intensity of the transmitted or reflected light), whereas ellipsometry measures the change in polarization of the light reflected at a surface. Because this change is characterized by an amplitude ratio and a phase shift (related to the reflection coefficients for light polarized in the plane and perpendicular to the plane of incidence),ellipsometry is highly accurate and reproducible, even for low light levels. In addition, it requires no reference sample, is less affected by sample scattering of light, and can be used to determine absolute values for the optical constants without independent thickness measurements. The project is expected to have a broad societal impact. One of its unique aspects will be the synergistic collaboration between ASU and industrial collaborators, who play a key role in the training of ASU personnel. Special emphasis will be placed on fostering scientific education. Funds are requested to support the operation of the instrument during the first year, and these funds will be expended primarily for the training of students. Industrial collaborators will play a key role in these activities, supervising students, providing samples, and teaching short courses on ellipsometry.