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利用兰州大学强流中子发生器出射的单能D-D中子对单晶TiO2(金红石相)进行辐照,分别测量了样品的正电子寿命谱及XRD谱。中子辐照会在样品内部产生大量的空位缺陷,由于晶格中Ti原子的位移阈能约为O原子的2倍,因此中子辐照在样品内部产生的空位缺陷以氧空位(VO)为主。结果表明,单晶内部捕获正电子的陷阱Ti空位(VTi)在中子辐照后电子密度增大,可能与Ti空位周围O空位的引入有关,O空位的出现减弱了Ti空位处的库仑排斥作用,使空位体积减少。后续测试的XRD也得到相同的结果,样品由于中子辐照而在c轴方向的晶面间距发生变化,并导致单晶TiO2的结晶度变差。
Single crystal D-D neutrons exiting the strong current neutron generator of Lanzhou University were used to irradiate the single crystal TiO2 (rutile phase), and the positron lifetime and XRD spectra of the samples were measured. Neutron irradiation will produce a large number of vacancy defects in the sample. Because the displacement threshold of Ti atoms in the lattice can be about twice that of O atoms, the vacancy defects generated by the neutron irradiation in the sample are expressed as oxygen vacancies (VO) Mainly. The results show that the trapped Ti vacancy (VTi) trapped inside the single crystal increases electron density after neutron irradiation, which may be related to the introduction of O vacancies around Ti vacancies. The occurrence of O vacancy weakens the Coulomb repulsion at Ti vacancies Role, to reduce the volume of vacancies. XRD of the subsequent tests also yielded the same results, with the samples varying in the c-axis plane spacing due to neutron irradiation and resulting in poor crystallinity of single crystal TiO2.