质子辐照对Yb掺杂ZnO稀磁半导体薄膜缺陷与磁性的影响

采用电感耦合等离子体增强物理气相沉积法制备了Yb掺杂ZnO薄膜, 并采用不同剂量质子对薄膜进行了辐照实验, 重点采用X射线衍射、光电子能谱、正电子湮灭图谱和磁测量系统对Zn_0.985Yb_0.015O薄膜的缺陷和磁性能进行了研究。磁性测试结果表明: Zn_0.985Yb_0.015O薄膜经质子辐照后其饱和磁化强度随辐照剂量的增加逐渐增大, 当辐照剂量为6 × 10¹⁵ ions/cm²时, 其饱和磁化强度达到最大, 随着辐照剂量的进一步增加, 其饱和磁化强度反而变小。正电子湮灭图谱结果显示薄膜中主要存在锌空位相关的缺陷, 并且锌空位相关的缺陷随辐照剂量的变化与饱和磁化强度随辐照剂量的变化相一致。本研究从实验上揭示了在含有各种缺陷的Yb掺杂ZnO薄膜中, 锌空位缺陷是影响质子辐照Zn_0.985Yb_0.015O薄膜磁性的主要原因。

Influence of Proton Irradiation on Defect and Magnetism of Yb-doped ZnO Dluted Magnetic Semiconductor Thin Films

Yb-doped ZnO thin films were prepared by inductively coupled plasma enhanced physical vapor deposition method, the as-deposited Zn_0.985Yb_0.015O thin films were irradiated by proton with different doses. X-ray diffraction, X-ray photoelectron spectroscopy, positron annihilation spectroscopy, and magnetic property measurement were used to study the defect and ferromagnetism. The magnetic property measurement results indicate that the saturation magnetization of Zn_0.985Yb_0.015O thin films increases with the increment of irradiation doses, and reaches the maximum value at 6×10¹⁵ ions/cm². With the further increase in irradiation doses, the saturation magnetization decreases. The positron annihilation measurement reveals that Zn vacancy-related defects dominate in proton irradiated Zn_0.985Yb_0.015O thin films. It is found that dependency of saturation magnetization on irradiation doses exhibits the same behavior with the amount of Zn vacancy-related defects on irradiation doses. It is experimentally demonstrated that the ferromagnetism of proton irradiated Yb-doped ZnO thin films is mainly influenced by Zn vacancy- related defects.