Bi_(1.6)La_(0.4)Ti_2O_7薄膜的制备及性能研究

采用化学溶液沉积法在ITO基片上制备不同退火温度的掺镧钛酸铋Bi1.6La0.4Ti2O7(BLT)薄膜。研究了其结构、介电性能、漏电流密度与外加电压I-V关系曲线和光学带隙。XRD射线衍射测试结果表明,经500、550、600℃1 h退火后的薄膜的主晶相为烧绿石结构,无杂相生成,600℃时BLT薄膜衍射峰比其他两种温度的强。在1 kHz频率下测得的介电常数、损耗因子分别为114,3%;129,3%;194,6%。BLT薄膜的漏电流密度与外加电压关系曲线表明,BLT薄膜600℃的漏电流比550和500℃稍微减小。通过透射谱分析得到BLT薄膜的光学带隙几乎不受温度影响,均为3.7 eV。这些结果表明制备BLT固溶体薄膜较佳为退火温度600℃,具有较好的性能,在光电器件有良好的应用前景。

Preparation and Properties ofBi1.6La0.4Ti2O7

Bi_1.6La_0.4Ti₂O₇（BLT） thin films were prepared on ITO glass substrates using a chemical solution deposition method. Their structures, dielectric properties, current-voltage I-V curves and optical constants were analyzed. The result of X-ray diffraction (XRD) analysis showed that the thin films annealed at 500, 550 and 600 ℃ for 1h were grown in pyrochlore structure and no secondary phase was detected. Also, the XRD peaks of BLT annealed at 600 ℃ was stronger than those annealed at other temperatures. The dielectric constant and dissipation factor (at 1 kHz) were 114 and 3%, 129 and 3%, 194 and 6%, respectively, for films annealed 500, 550 and 600 ℃. Leakage current densities of BLT thin films versus applied voltage curves suggested that the value of leakage current for films annealed at 600 ℃ was much smaller than those annealed at 500 and 550 ℃. The annealing temperature had little effect on the optical band gap of the films with the values of 3.7 eV. These results indicated that the BLT thin films annealed at 600 ℃ had an excellent property, and they had a potential application in opticoelectric devices.