Optical studies of pure and (Cu, Co) doped nickel zinc ferrite films deposited on quartz substrate
Optical studies of pure and (Cu, Co) doped nickel zinc ferrite films deposited on quartz substrate
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DOI：
10.1116/6.0002262
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Sneha Kothapally;S. Kotru;R. Paul;J. A. Abu Qahouq
中科院分区：
文献类型：
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作者：
Sneha Kothapally;S. Kotru;R. Paul;J. A. Abu Qahouq
在这项工作中，研究了纯薄膜和掺杂薄膜的光学特性与退火温度的关系。采用溶胶-凝胶法将成分为 Ni0.5Zn0.5Fe2O4、Ni0.35Cu0.2Zn0.45Fe2O4 和 Ni0.35Co0.2Zn0.45Fe2O4 的薄膜沉积在石英基板上。生长的薄膜在快速热退火炉中在 500 和 800 °C 下进行退火。 X 射线衍射 (XRD) 结果证实了这些薄膜的单相尖晶石结构。从 XRD 数据计算出的平均晶粒尺寸随着退火温度的增加而增加，对于掺杂 Cu 和 Co 的薄膜则减小。晶格常数随着退火温度的增加而减小，而对于掺杂 Cu 和 Co 的薄膜则增加。从场发射扫描电子显微镜获得的横截面图像用于计算这些薄膜的厚度。紫外可见分光光度法用于获取 200-800 nm 范围内波长函数的吸收光谱。对于纯膜和掺杂膜，在较高温度下退火的膜从吸收光谱获得的带隙减小。此外，与纯薄膜相比，掺杂薄膜的带隙有所减小。观察到折射率、消光系数、光导率以及介电常数的实部和虚部等光学参数随着带隙的减小而增加。
In this work, the optical properties of pure and doped films were investigated as a function of annealing temperature. Films with compositions Ni0.5Zn0.5Fe2O4, Ni0.35Cu0.2Zn0.45Fe2O4, and Ni0.35Co0.2Zn0.45Fe2O4 were deposited on quartz substrate using the sol–gel method. The grown films were annealed at 500 and 800 °C in a rapid thermal annealing furnace. The single-phase spinel structure of these films was confirmed by x-ray diffraction (XRD) results. The average crystallite size calculated from the XRD data was observed to increase with the annealing temperature and decrease for films doped with Cu and Co. The lattice constant was observed to decrease with the annealing temperature and increase for films doped with Cu and Co. The cross-sectional images obtained from field emission scanning electron microscope were used to calculate the thickness of these films. Ultraviolet-visible spectroscopy was used to obtain the absorbance spectra as a function of wavelength in the range of 200–800 nm. The bandgap obtained from the absorbance spectra was seen to decrease for films annealed at higher temperatures for pure and doped films. Furthermore, the bandgap of doped films was seen to decrease in comparison to that of pure films. Optical parameters such as refractive index, extinction coefficient, optical conductivity, and real and imaginary parts of the dielectric constant were observed to increase with the reduction in the bandgap.