| Co掺杂纳米ZnO微结构的正电子湮没研究 |
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| 引用本文： | 祁宁,王元为,王栋,王丹丹,陈志权.Co掺杂纳米ZnO微结构的正电子湮没研究[J].物理学报,2011,60(10):107805-107805. |
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| 作者姓名： | 祁宁 王元为 王栋 王丹丹 陈志权 |
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| 作者单位： | 武汉大学物理科学与技术学院核固体物理湖北省重点实验室,武汉 430072 |
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| 基金项目： | 国家自然科学基金(批准号:10875088,11075120)和国家自然科学基金国家基础科学人才培养基金(批准号:J0830310)资助的课题. |
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| 摘 要： | 利用正电子湮没技术研究了10 at.% Co掺杂的Co3O4/ZnO纳米复合物中退火对缺陷的影响. 利用X射线衍射(XRD)测量了Co3O4/ZnO纳米复合物的结构和晶粒尺寸. 随着退火温度升高,Co3O4相逐步消失,ZnO晶粒尺寸也有显著增加. 经过1000 ℃以上退火后,Co3O4相完全消失,并出现了CoO的岩盐结构. 正电子湮没寿命测量显示出Co3O4 /ZnO纳米复合物中存在大量的Zn空位和空位团. 这些空位缺陷可能存在于纳米复合物的界面区域. 当退火温度达到700 ℃后Zn空位开始恢复,空位团也开始收缩. 900 ℃以上退火后,所有空位缺陷基本消失,正电子寿命接近ZnO完整晶格中的体态寿命值. 符合多普勒展宽谱测量也显示Co3O4 /ZnO纳米复合物经过900 ℃以上退火后电子动量分布与单晶ZnO基本一致,表明界面缺陷经过退火后得到消除.
关键词：
ZnO
界面缺陷
正电子湮没
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| 关 键 词： | ZnO 界面缺陷 正电子湮没 |
| 收稿时间： | 2010-11-29 |
| 修稿时间： | 1/4/2011 12:00:00 AM |
Positron annihilation study of the microstructure of Co doped ZnO nanocrystals |
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| Qi Ning,Wang Yuan-Wei,Wang Dong,Wang Dan-Dan and Chen Zhi-Quan.Positron annihilation study of the microstructure of Co doped ZnO nanocrystals[J].Acta Physica Sinica,2011,60(10):107805-107805. |
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| Authors: | Qi Ning Wang Yuan-Wei Wang Dong Wang Dan-Dan and Chen Zhi-Quan |
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| Institution: | Hubei Nuclear Solid Physics Key Laboratory, School of Physics, Wuhan University, Wuhan 430072, China;Hubei Nuclear Solid Physics Key Laboratory, School of Physics, Wuhan University, Wuhan 430072, China;Hubei Nuclear Solid Physics Key Laboratory, School of Physics, Wuhan University, Wuhan 430072, China;Hubei Nuclear Solid Physics Key Laboratory, School of Physics, Wuhan University, Wuhan 430072, China;Hubei Nuclear Solid Physics Key Laboratory, School of Physics, Wuhan University, Wuhan 430072, China |
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| Abstract: | ZnO nanopowders are mechanically mixed with a certain quantity of Co3O4 nanopowders to obtain 10at.% Co doped Co3O4/ZnO composites. The nanocomposites are annealed in argon atmosphere at different temperatures between 100 ℃ and 1200 ℃. The structure and the grain size of the nanocomposite are investigated by X-ray diffraction 2θ scans. With annealing temperature increasing up to 700 ℃, Co3O4 phase gradually disappears, and ZnO grain size begins to increase significantly. After annealing at above 1000 ℃, Co3O4 phase completely disappears, and CoO phase (rock-salt crystal structure) appears. Positron annihilation lifetime measurements reveal a large number of Zn vacancies and vacancy clusters existing in the interface region of the Co3O4 /ZnO nanocomposites. These defects are gradually recovered after annealing at above 700 ℃, and their number is under the detection limit after annealing at 900 ℃. The same conclusion can be drawn from the coincidence Doppler broadening (CDB) measurements. |
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| Keywords: | ZnO nanocomposites interface defects positron annihilation |
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