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Surface segregation of W doped in ZnO thin films
被引:9
作者:
Suzuki, T. T.
[1
]
Adachi, Y.
[1
]
Saito, N.
[1
]
Hashiguchi, M.
[1
]
Sakaguchi, I.
[1
]
Ohashi, N.
[1
]
Hishita, S.
[1
]
机构:
[1] Natl Inst Mat Sci, Tsukuba, Ibaraki 3050044, Japan
来源:
关键词:
Surface segregation;
Ion scattering spectroscopy;
Tungsten;
Zinc oxide;
PHOTOCATALYTIC DEGRADATION;
COMPOSITE POWDERS;
ION-SCATTERING;
TUNGSTEN;
SAPPHIRE;
GROWTH;
WO3;
POLARITY;
DRIVEN;
DYE;
D O I:
10.1016/j.susc.2014.02.014
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
We observed surface segregation of W (0.05-4 mol%) doped in ZnO films by annealing above 900 K. The segregation coefficient was related to the crystal quality of the film, where slower segregation occurs in higher-quality crystalline films. Using low-energy He+ ion scattering spectroscopy for structure analysis, we found that the W-ZnO surface terminates with an O-layer, and W is located in a substitutional site of Zn at the second surface layer as a consequence of segregation. On the other hand, we observed no indication that W occupies certain sites in the ZnO lattice at the subsurface. Ultraviolet photoelectron spectroscopy (He I) on the W-segregated ZnO surface indicates that W is hexavalent at the Zn site. The segregation of the W atom is likely accompanied by two Zn vacancies. Ion beam mixing followed by annealing of the ZnO surface deposited with W provides a surface electronic structure similar to that of W-segregated ZnO. (C) 2014 Elsevier B.V. All rights reserved.
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页码:1 / 6
页数:6
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