Bi₁₂MO₂₀ (M: Si, Ge, Ti, etc.) compounds are known as sillenites having fascinating photorefractive characteristics. The present paper reports the structural and optical characteristics of one of the members of this family, Bi₁₂TiO₂₀ single crystals, grown by Czochralski method. X-ray diffraction pattern of the crystal presented sharp and intensive peaks associated with planes of cubic crystalline structure with lattice constant of a = 1.0142 nm. The optical properties were studied by means of room temperature Raman and temperature-dependent transmission experiments at various temperatures between 10 and 300 K. Raman spectrum indicated peaks around 127, 162, 191, 219, 261, 289, 321, 497 and 537 cm⁻¹. The analyses of transmittance spectra indicated the increase of direct bandgap energy from 2.30 to 2.56 eV as temperature was decreased from room temperature to 10 K. The temperature-dependent bandgap characteristics of Bi₁₂TiO₂₀ were analyzed by means of Varshni and O’Donnell-Chen models. The analyses under the light of these models resulted in absolute zero bandgap energy of E_g(0) = 2.56(4) eV, rate of change of bandgap energy of γ = – 1.11 × 10⁻³ eV/K and average phonon energy of 〈E_ph〉 = 8.6 meV.

Bi ₁₂ MO ₂₀（M：Si，Ge，Ti等）化合物被称为具有迷人的光折变特性的亚硅酸盐。本文报道了该家族成员之一，通过切克劳斯基方法生长的Bi ₁₂ TiO ₂₀单晶体的结构和光学特性。晶体的X射线衍射图谱显示出与立方晶结构的平面相关的尖峰和强峰，晶格常数为a  = 1.0142 nm。通过室温拉曼光谱和在10至300 K之间的各种温度下依赖于温度的透射实验研究了光学性质。拉曼光谱表明在127、162、191、219、261、289、321、497和537 cm附近出现峰^-1。透射光谱分析表明，随着温度从室温降低到10 K，直接带隙能量从2.30 eV增加到2.56 eV。利用Varshni和O'Donnell-分析了Bi ₁₂ TiO ₂₀随温度变化的带隙特性。陈模特。根据这些模型进行分析，得出的绝对零带隙能量为E _g（0）= 2.56（4）eV，γ的带隙能量变化率为 = = 1.11×10 ^-3  eV / K，平均声子能量为＜E _ph＞ ＝ 8.6meV。