Structural characterization of diamond-like carbon films for ultracold neutron applications
Structural characterization of diamond-like carbon films for ultracold neutron applications
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DOI：
10.1016/j.diamond.2006.06.008
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发表时间：
2007-02-01
影响因子：
4.1
通讯作者：
Straumann, U.
中科院分区：
文献类型：
--
作者：
Atchison, F.;Brys, T.;Straumann, U.
我们通过真空电弧沉积生产了无氢类金刚石碳 (DLC) 薄膜，用作超冷中子 (UCN) 应用中的壁涂层材料。 sp(3) 分数（UCN 应用中使用的 DLC 的主要品质因数）在 0.4 至 0.9 之间变化，涂层厚度在 10 nm 至 120 nm 之间。使用 X 射线吸收近边光谱 (XANES)、X 射线诱导光电子能谱 (XPS)、激光诱导表面声波 (LAwave)、冷中子反射法和可见光激发波长的拉曼光谱对样品进行表征。我们观察到膜厚度低于 20 nm 的不同结果之间有合理的一致性。对于较大的厚度，我们发现表面敏感方法 XPS 和 XANES 比体敏感 LAwave 产生更小的 sp(3) 分数（最多 20%），这与标称密度体层上较低密度表面层的假设一致。 (c) 2006 Elsevier B.V. 保留所有权利。
We have produced hydrogen-free diamond-like carbon (DLC) films by vacuum arc deposition for use as wall coating material in ultracold neutron (UCN) applications. The sp(3) fraction, the main quality factor for DLC used in UCN applications, was varied from 0.4 to 0.9, the coating thickness between 10 nm and 120 nm. The samples were characterized by using X-ray Absorption Near-Edge Spectroscopy (XANES), X-ray induced Photoelectron Spectroscopy (XPS), Laser induced surface Acoustic Waves (LAwave), cold neutron reflectometry and Raman spectroscopy at visible excitation wavelength. We observe reasonable agreement between the different results for film thicknesses below 20 nm. For larger thickness, we find that the surface-sensitive methods XPS and XANES yield smaller sp(3) fractions (by up to 20%) than the bulk-sensitive LAwave, being consistent with the assumption of a lower-density surface layer on a nominal-density bulk layer. (c) 2006 Elsevier B.V. All rights reserved.