In this study, BFO and BFAO thin films were prepared on fluorine-doped tin oxide (FTO) substrates via spin coating with two different acid solvents. One is nitric acid solution (solvent I), the other is a mixture of 2-methoxyethanol and glacial acetic acid (solvent II). The structure, morphology, elemental valence states, and ferroelectric properties of BiFeO₃ (BFO) and BiFe_0.96Al_0.04O₃ (BFAO) films were investigated. X-ray diffraction (XRD) results show that all the films are R3c structure and have no impurity phase. The SEM results show that the BFO thin film prepared by solvent II is more compact, uniform, and has low porosity. Raman spectra show that Al doping causes structural distortion. Al doping can solve the problem of porosity and increase the density of BFO thin film. Therefore, the density of BFAO-II sample is better. X-ray photoelectron spectroscopy (XPS) shows that the presence of Al reduces the oxygen vacancy content. This is beneficial to reduce the leakage current density and improve the ferroelectric properties. The leakage current density of BFAO-II sample is 10^-3 A/cm², and the double residual polarization value is 110.2 μC/cm². Compared with BFO-II sample, it is significantly improved. In addition, Al doping can reduce the band gap of BFO films. This work will be a new idea for the further application of Al doped bismuth ferrite films.

在这项研究中，通过用两种不同的酸性溶剂旋涂在掺氟氧化锡（FTO）衬底上制备BFO和BFAO薄膜。一种是硝酸溶液（溶剂I），另一种是2-甲氧基乙醇和冰醋酸的混合物（溶剂II）。研究了BiFeO ₃（BFO）和BiFe _0.96 Al _0.04 O ₃（BFAO）薄膜的结构，形态，元素价态和铁电性能。X射线衍射（XRD）结果表明，所有薄膜均为R3c结构，无杂质相。SEM结果表明，用溶剂Ⅱ制备的BFO薄膜更致密，均匀，孔隙率低。拉曼光谱表明，Al掺杂会导致结构变形。铝掺杂可以解决气孔问题并增加BFO薄膜的密度。因此，BFAO-II样品的密度更好。X射线光电子能谱（XPS）表明，Al的存在降低了氧空位含量。这有利于降低漏电流密度并改善铁电性能。BFAO-II样品的漏电流密度为10 ^-3 A / cm ²，双残留极化值为110.2μC/ cm ²。与BFO-II样品相比，它得到了显着改善。另外，Al掺杂可以减小BFO膜的带隙。这项工作将成为进一步应用铝掺杂铋铁氧体薄膜的新思路。