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室温稀磁半导体是自旋电子器件研究的关键途径,但其室温铁磁性的内禀性及其起源的研究有争议。正电子湮没谱学方法(PAS)是研究材料缺陷的重要实验手段。为了建立缺陷结构与材料铁磁性之间的相互关系,用离子注入法制备了注入剂量不同的Co离子掺杂金红石TiO2晶体薄膜,在北京慢正电子束流装置上以不同的入射电子能量测量了样品的正电子湮没多普勒展宽能谱(DBS)和正电子符合多普勒展宽谱(CDB),分析样品的缺陷浓度和缺陷类型。DBS谱的S参数和W参数分析表明,Co离子的注入使样品出现了新的湮没机制。CDB谱的商谱分析说明,Co离子注入TiO2晶体后产生了Ti-Co-VO型和Ti-VO型氧空位复合体,样品中空位浓度随Co离子注入剂量有所增加,它是由氧空位周围过剩的Ti原子的3d电子所引起。
Room temperature dilute magnetic semiconductors are the key ways to study spintronic devices, but the research on their intrinsic ferromagnetism and its origin has been controversial. Positron annihilation spectroscopy (PAS) is an important experimental method for studying material defects. In order to establish the relationship between the defect structure and the ferromagnetism of the material, a Co-doped rutile TiO2 crystal film with different implantation dose was prepared by ion implantation method. The film was measured with different incident electron energies The positron annihilation Doppler spectrum (DBS) and positron emission matching (Doppler) broadening spectrum (CDB) of the samples were used to analyze the defect concentration and defect types of the samples. The S parameter and W parameter analysis of DBS spectrum show that the injection of Co ions makes the sample appear a new annihilation mechanism. The analysis of the CDB spectra shows that the Ti-Co-VO and Ti-VO oxygen vacancy complexes are formed after the Co ions are implanted into the TiO2 crystal. The vacancy concentration in the sample increases with the dose of Co ion implantation. Around the excess Ti atoms caused by 3d electrons.