Electronic structure of carbon nitride thin films studied by X-ray spectroscopy techniques
Electronic structure of carbon nitride thin films studied by X-ray spectroscopy techniques
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DOI：
10.1016/j.tsf.2004.03.027
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发表时间：
2005-01-03
期刊：
影响因子：
2.1
通讯作者：
Sundgren, JE
中科院分区：
文献类型：
--
作者：
Hellgren, N;Guo, JH;Sundgren, JE
采用X射线光电子能谱（XPS）、紫外光电子能谱（UPS）、近边X射线吸收精细结构谱（NEXAFS）和X射线发射谱（XES）对磁控溅射制备的不同结构和成分的氮化碳薄膜进行了分析。在所有的技术中，碳谱是宽的，并且没有特征，根据生长条件几乎没有变化。另一方面，氮光谱显示出更明显的特征，为结构表征提供了有力的工具。通过比较实验光谱与不同模型系统的计算，我们能够确定氮-N1的三种主要键合结构：腈（C相当于N）键; N2：吡啶类N，即，N3：石墨状N，即，N键合到三个C原子上，就像在石墨网络中被取代一样，然而，可能位于五边形中和/或与sp（3）碳相邻。N2和N3的存在最好通过XPS检测，而N1最好通过NEXAFS检测。计算的XES谱也给出了很好的指示如何解释价带谱。在较高的温度（大于或等于350 degreesC）下生长的薄膜显示出显着的角度依赖性的入射光子束在NEXATS测量，这表明一个纹理化的微观结构与站立的石墨基面，而在低温下生长的非晶薄膜显示各向同性的属性。(C)2004 Elsevier B. V.保留所有权利。
Magnetron-sputtered carbon nitride thin films with different structures and compositions were analyzed by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), as well as X-ray emission spectroscopy (XES). In all techniques, the carbon spectra are broad and featureless with little variation depending on growth conditions. The nitrogen spectra, on the other hand, show more distinct features, providing a powerful tool for structural characterization. By comparing the experimental spectra with calculations on different model systems, we are able to identify three major bonding structures of the nitrogen-N1: nitrile (C equivalent to N) bonds; N2: Pyridine-like N, i.e., N bonded to two C atoms; and N3: graphite-like N, i.e., N bonded to three C atoms as if substituted in a graphitic network, however, possibly positioned in a pentagon and/or with sp(3) carbon neighbors. The presence of N2 and N3 are best detected by XPS, while N1 is better detected by NEXAFS. The calculated XES spectra also give good indications how valence band spectra should be interpreted. Films grown at the higher temperatures ( greater than or equal to 350 degreesC) show a pronounced angular dependence of the incoming photon beam in NEXATS measurements, which suggests a textured microstructure with standing graphitic basal planes, while amorphous films grown at low temperatures show isotropic properties. (C) 2004 Elsevier B.V. All rights reserved.