Identification of nitrogen chemical states in N-doped ZnO via x-ray photoelectron spectroscopy
Identification of nitrogen chemical states in N-doped ZnO via x-ray photoelectron spectroscopy
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DOI：
10.1063/1.1847728
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发表时间：
2005-02-01
影响因子：
3.2
通讯作者：
Coutts, TJ
中科院分区：
文献类型：
--
作者：
Perkins, CL;Lee, SH;Coutts, TJ
利用X射线光电子能谱(XPS)和紫外光电子能谱(UPS)研究了金属有机化学气相沉积(MOCVD)和反应溅射两种方法制备的掺氮氧化锌薄膜。观察到溅射和MOCVD生长的薄膜在N化学态上的系统差异：在反应溅射薄膜中只观察到两种N化学态，而在MOCVD薄膜中观察到四种N化学态。为了辅助N化学态的指定，我们将多晶薄膜的光电子能谱数据与N-2(+)离子注入的锌金属和N-2(+)离子注入的氧化锌的数据进行了比较。N1S区的高分辨率核能级光谱表明，氮在氧化锌中至少可以占据四种不同的化学环境，包括N-O受体、双施主(N-2)(O)和两个碳-氮物种。价带谱表明，所有薄膜的费米能都在导带最小值附近，说明氮掺杂后薄膜仍然是n型的。XPS对溅射生长的薄膜中受主和施主的相对数量的分析提供了线索，解释了为什么只有一小部分掺入的氮对载流子有贡献，并指出了获得更高质量的ZnO：N薄膜的可能途径。(C)2005年美国物理研究所。
Nitrogen-doped films of ZnO grown by two methods, metalorganic chemical vapor deposition (MOCVD) and reactive sputtering, were studied with x-ray and ultraviolet photoelectron spectroscopy (XPS and UPS). Systematic differences in the N chemical states were observed between films grown by sputtering and MOCVD: only two N chemical states were observed in films grown by reactive sputtering, whereas four N chemical states were observed in MOCVD films. To aid in the assignment of the N chemical states, photoemission data from the polycrystalline films were compared with data taken on N-2(+)-implanted Zn metal and N-2(+)-implanted ZnO. High-resolution core level spectra of the N 1s region indicated that nitrogen can occupy at least four different chemical environments in ZnO; these include the N-O acceptor, the double donor (N-2)(O), and two carbon-nitrogen species. Valence band spectra indicate that the Fermi energy of all films studied was near the conduction band minimum, implying that the films remained n-type after nitrogen doping. Analysis of the relative amounts of acceptors and donors identified by XPS in the sputter-grown films provides clues as to why only a small percentage of incorporated nitrogen is found to contribute to carriers, and points toward possible paths to higher quality ZnO:N films. (C) 2005 American Institute of Physics.