Defect-induced magnetism in undoped and Mn-doped wide band gap zinc oxide grown by aerosol spray pyrolysis
Defect-induced magnetism in undoped and Mn-doped wide band gap zinc oxide grown by aerosol spray pyrolysis
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DOI：
10.1016/j.apsusc.2014.04.183
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发表时间：
2014-08
影响因子：
6.7
通讯作者：
D. Motaung;I. Kortidis;D. Papadaki;S. Nkosi;G. H. Mhlongo;J. Wesley-Smith;G. Malgas;B. Mwakikunga;E. Coetsee;H. Swart;G. Kiriakidis;S. Ray
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文献类型：
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作者：
D. Motaung;I. Kortidis;D. Papadaki;S. Nkosi;G. H. Mhlongo;J. Wesley-Smith;G. Malgas;B. Mwakikunga;E. Coetsee;H. Swart;G. Kiriakidis;S. Ray
本文系统地研究了不同沉积时间下未掺杂和Mn掺杂ZnO薄膜的结构、光学和磁性能。XRD分析表明，制备的产物为纤锌矿结构，无第二相存在。表面形貌分析表明，Mn在ZnO基体中的掺入导致了“甜甜圈”结构的形成，而相应的未掺杂ZnO只有在较长的沉积时间才呈现出渗透性结构。光学结果表明，Mn掺杂的ZnO纳米结构在595 nm处表现出与Mn2+离子相关的橙色特征发射，在667nm处表现出肩部，表明Mn离子成功占据了Zn离子的晶格位置。EDX和XPS分析了掺杂ZnO纳米结构中Mn离子的化学组成和电荷态，也证实了Mn2+离子成功地结合到ZnO主体晶体中的锌位点上。结合基于PL和XPS的缺陷分析，通过EPR研究了缺陷对铁磁性性质和来源的影响。这些结果表明，锌和氧缺陷，特别是锌间隙和单离子氧空位，在未掺杂ZnO的铁磁性介质中起着至关重要的作用。
We present a systemic study on the structural, optical and magnetic properties of the un-doped and Mn doped ZnO thin films grown by aerosol spray pyrolysis at different deposition times. XRD profiling has shown that the structures of the prepared products are wurtzite without any evidence of second phases. Surface morphology analysis revealed that incorporation of Mn in the ZnO matrix results in the formation of “doughnut-like” structures while the corresponding un-doped ZnO showed permeable structures only at long deposition time. Optical results demonstrated that Mn-doped ZnO nanostructures exhibited both the characteristic orange Mn2+ion-related emission at 595 nm and a shoulder around 667 nm, denoting that the Mn ions have successfully occupied lattice positions of Zn ions. The chemical composition and charge states of the Mn ions in the doped ZnO nanostructures analysed by the EDX and XPS, also confirmed that Mn2+ions were successfully incorporated onto zinc sites in the ZnO host crystal. With the combination of defect analysis based on PL and XPS, the effect of defects on the nature and origin of ferromagnetism through EPR was investigated. These findings suggested that zinc and oxygen defects, especially zinc interstitials and singly ionized oxygen vacancies, play a crucial role in mediating ferromagnetism in the undoped ZnO.