F掺杂对溶胶-凝胶法制备的ZnO∶Fe薄膜结构及光学性质的影响

Effects of F Doping on the Crystal Structures and Optical Properties of ZnO∶Fe Thin Films Prepared by Sol-gel Method

采用溶胶-凝胶法在玻璃衬底上制备了Zn0.98-xFe0.02FxO(x=0,0.01,0.02,0.03,0.04)薄膜,进而利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见透过谱(UV-VIS)、光致发光(PL)多种测试手段研究了不同掺F浓度对Zn O∶Fe薄膜的表面形貌、微结构、禁带宽度及光致发光的影响。结果表明:样品均为六角纤锌矿结构,当F掺杂浓度为2at%时,薄膜的结晶度最好且表现出明显的c轴择优取向。随着F掺杂浓度的进一步增大,薄膜的结晶性逐渐变差,c轴择优取向消失。F掺杂Zn O∶Fe薄膜在可见光区均有很高的透过率,平均可达93%。样品的禁带宽度随着掺F浓度的增加而减小。PL谱观察到Zn0.98-xFe0.02FxO薄膜的发射峰主要由紫外发射峰和蓝光发射峰组成,其中2at%F掺杂样品的紫外发射强度最大,同时蓝光发射强度随着F含量的增大逐渐减小。

Zn0. 98-xFe0. 02 FxO thin films were synthesized on glass substrates by sol-gel method. The effects of F doping concentrations on the surface morphology, structures, optical bandgap and photoluminescence of Zn O ∶ Fe thin films were analyzed by SEM,XRD,UV-VIS transmittance spectra and photoluminescence（ PL）,respectively. The results show that all the films exhibit hexagonal wurtzite structure. After 2at% F is doped,the crystalline quality and the preferential orientation of the Zn O film improved. As the F-doping concentration increasing,the crystalline quality and preferential orientation of Zn O films become poor. F-incorporation hardly influences the transmittance in the visible region. All the samples show high transmittance with the average value above 93% in the visible region. Optical bandgaps of the Zn O ∶ Fe films slightly decrease as F-doping concentration increasing. The PL spectra measured at room temperature display that all the samples exhibit an ultraviolet emission peak,but for thecase of 2at% F-doping,the Zn O ∶ Fe film shows the strongest ultraviolet emission peak. Weak blue emission peak are also observed for all samples. The intensity of blue emission is reduced with the increase of F-doping concentration.