退火温度对N+注入ZnO:Mn薄膜结构及室温铁磁性的影响

采用射频磁控溅射法在石英玻璃衬底上制备了ZnO:Mn薄膜, 结合N⁺ 注入获得Mn-N共掺ZnO薄膜, 进而研究了退火温度对其结构及室温铁磁性的影响. 结果表明, 退火后ZnO:(Mn, N) 薄膜中Mn²⁺和N^3-均处于ZnO晶格位, 没有杂质相生成. 退火温度的升高 有助于修复N⁺注入引起的晶格损伤, 同时也会让N逸出薄膜, 导致受主(N_O)浓度降低. 室温铁磁性存在于ZnO:(Mn, N)薄膜中, 其强弱受N_O浓度的影响, 铁磁性起源可采用束缚磁极化子模型进行解释.

Effects of the annealing temperature on microstructure and room-temperature ferromagnetism of N+ ion-implanted ZnO: Mn thin film

The Mn-N codoped ZnO thin films are fabricated on quartz glass substrates using the radio-frequency magnetron sputtering technique together with the direct N⁺ ion-implantation. The effects of annealing temperature on microstructure and room-temperature ferromagnetism of the thin films are investigated. The results indicate that both divalent Mn²⁺ and trivalent N^3- ions are incorporated into ZnO lattice. As the annealing temperature increases, the lattice distortion induced by N⁺ ion-implantation can decrease, and the N^3- may escape from the film, which results in the reducing of acceptor (N_O) concentration. Ferromagnetism is observed in the (Mn,N)-codoped ZnO thin film at 300 K and found to be the sensitive to the acceptor concentration. The mechanism of room-temperature ferromagnetism in the ZnO:(Mn, N) is discussed based on the bound magnetic polaron model.