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利用正电子湮没技术研究了10at.%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.
The positron annihilation technique was used to study the effect of annealing on the defects in 10at.% Co-doped Co3O4 / ZnO nanocomposites. The structure and grain size of Co3O4 / ZnO nanocomposites were measured by X-ray diffraction With the increase of annealing temperature, the phase of Co3O4 gradually disappeared and the grain size of ZnO also increased remarkably.The Co3O4 phase disappeared completely and the rock salt structure of CoO appeared after annealing above 1000 ℃ .The positron annihilation lifetime measurement showed that Co3O4 / ZnO nano There are a large number of Zn vacancies and vacancy clusters in the complex.These vacancy defects may exist in the nanocomposite interface area.When annealing temperature reaches 700 ℃ Zn vacancy began to recover the vacancy cluster began to shrink.After 900 ℃ annealing above all The vacancies disappeared and the positron lifetime was close to that of the complete lattice of ZnO. Comparing with the Doppler broadening spectrum measurement, the electron momentum distribution of Co3O4 / ZnO nanocomposites after annealed above 900 ℃ was basically the same as that of single crystal ZnO. It shows that the interface defects are eliminated after annealing.