退火温度对N^+注入Zno:Mn薄膜结构及室温铁磁性的影响

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

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Mn^(2+)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(No)浓度降低.室温铁磁性存在于ZnO:(Mn,N)薄膜中,其强弱受No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.

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 N3- ions are incorporated into ZnO lattice. As the annealing temperature increases, the lattice distortion induced by N＋ ion-implantation can decrease, and the N3- may escape from the film, which results in the reducing of acceptor （No） 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 roomtemperature ferromagnetism in the ZnO：（Mn, N） is discussed based on the bound magnetic polaron model.