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利用金属有机源化学气相沉积技术,通过改变受主掺杂源和导入氢气并提高生长压力来逐步抑制C的办法,在蓝宝石上外延了Mn,N共掺ZnO薄膜.X射线衍射显示所有样品都具有良好的单轴取向.ZnMnO:N样品的Raman光谱中C元素相关的振动模明显消失.同时van der Pauw法Hall效应测量表明,通过逐步对C的抑制,样品由n型导电转变成p型导电,这主要是由于C与N形成复合体取代O位(CN)_O,具有最低形成能且充当浅施主.对N,Mn共掺ZnO晶体的第一性原理模拟计算显示了N,Mn共掺ZnO的态密度在Fermi能级处存在较强的自旋极化,表明N 2p电子与Mn 3d电子之间存在较强的p-d相互作用,形成磁性束缚激子产生磁矩.一旦引入C后,C,N形成复合体取代O位,导致体系磁性减弱或者消失.模拟计算结果与实验表征分析结果一致表明:对于Mn,N共掺ZnO薄膜样品,引入C与N形成复合体取代O位,Mn,N共掺ZnO薄膜磁性减弱或消失.因此,Mn 3d电子与N 2p局域束缚的电子形成的磁性束缚激子决定了Mn,N共掺ZnO薄膜室温铁磁信号的产生.
Mn and N codoped ZnO thin films were epitaxially grown on sapphire by metal-organic chemical vapor deposition (CVD) by changing acceptor doping source, introducing hydrogen and increasing the growth pressure to suppress the formation of C. X-ray diffraction showed that all samples With good uniaxial orientation.The vibrational modes of C element in the Raman spectrum of ZnMnO: N samples disappeared obviously, and the Hall effect measurement of van der Pauw method showed that the sample was changed from n-type conductivity to p-type conductivity Which is mainly due to the fact that C and N form a complex instead of O (CN) _O, which has the lowest formation energy and acts as a shallow donor. The first-principles simulation calculation of N and Mn codoped ZnO crystals shows that N and Mn There is a strong spin polarization in the state density of ZnO doped at the Fermi level, indicating strong pd interaction between N 2p electrons and Mn 3d electrons to form magnetic bound excitons to generate magnetic moment. Once introduced into C , C and N to replace the O site, resulting in weakening or disappearance of the magnetism.The simulation results agree well with those of the experimental characterization: for the Mn and N codoped ZnO thin films, a composite of C and N is introduced to replace the O site, Mn, N co-doped ZnO thin film magnetic weakened or disappeared. Here, the electrons of the magnetic Mn 3d and N 2p electrons bound exciton bound local decision Mn, at room temperature to produce a thin film ferromagnetic co-doped ZnO N signal.