Co掺杂ZnO薄膜的结构及光磁性能研究

Study of Structural,Photoluminescent and Magnetic Properties of Co-doped ZnO Thin Films

采用溶胶-凝胶旋涂法在玻璃衬底上制备了Zn1-xCoxO(x=0,0.01,0.03,0.05,0.08,0.12)薄膜.利用显微镜和X射线衍射(XRD)研究了ZnO:Co薄膜的表面形貌和微结构.结果表明,所有ZnO薄膜样品都存在(002)择优取向,尤其是当掺杂浓度为12%时,薄膜c轴择优取向最为显著.振动样品磁强计(VSM)测量表明Zn1-xCoxO薄膜具有室温铁磁性.室温光致发光测量发现,所有样品的PL谱中都出现了较强的蓝光双峰发射和较弱的绿光发射,分析认为这主要是由于Co元素的掺入改变了薄膜的禁带宽度、锌填隙缺陷和氧位错缺陷浓度,其中长波长的蓝光峰和绿光峰都能够通过掺杂进行控制.基于上面的测量结果,探讨了不同波段光发射的机理与掺杂状态之间的关系.

Zn1-xCoxO thin films were deposited on the glass substrate by means of sol-gel method.The influence of Co doping on surface morphologies of ZnO films have been investigated.The microstructures of the thin films were investigated by X-ray diffraction（XRD）.It is indicated that all the ZnO samples show preferential orientation along（002） direction,and the thin films have the best c-axis oriented grains when doping concentration up to 12%.The vibrating sample magnetometer（VSM） measured the ferromagnetic properties of Zn0.95Co0.05O thin films at room temperature.Strong blue double emission and weak green emission were observed in photoluminescent spectrum of all samples at room temperature.Both blue emission and green PL peak could be modulated by controlling the doping level.This is due to Co doping concentration affected band gap,zinc interstial defect concentration and oxygen dislocation defect concentration.In addition,the relationship of the luminescence mechanism and the different doping states was also discussed.