蓝宝石中子辐照色心的研究

研究了中子辐照对蓝宝石(α-Al2O3)单晶体缺陷形成及光学性能的影响，对采用提拉法与温度梯度法生长的蓝宝石晶体进行中子辐照，通过对比辐照前后的吸收及荧光光谱变化，发现辐照使得蓝宝石晶体内形成F、F^ 和F2^ 色心缺陷，但不同方法生长的晶体样品中色心浓度差异明显。其中提拉法样品的F心浓度要高于温度梯度法样品，而温度梯度法样品中F^ 色心浓度要高于提拉法样品。分析表明，这与两种方法生长的晶体中杂质含量差异有关。通过研究辐照后晶体的热致发光谱发现提拉法与温度梯度法生长的蓝宝石晶体分别在145℃与150℃有明显的热致发光出现，采用初始上升法计算出两种方法生长的晶体的热致发光陷阱深度分别为1．15eV及1．05eV。

Investigation of Color Centers in Sapphire Induced by Neutrons Irradiation

Neutron-irradiation induced defects formation and optical properties change in sapphire (α-Al2O3) are discussed. Czochralski (CZ) and temperature gradient technique (TGT) grown sapphire crystals are irradiated by neutrons, and F, F+ and F+2 color centers are formed in both crystals according to absorption and fluorescence spectra. But the concentration of color centers is different. Concentration of F+ center in TGT crystals is higher than that in CZ samples, while the F center concentration in CZ crystals is higher than that in TGT crystal. It is attributed to different impurities concentration of sapphire samples. Obvious thermoluminescence peaks at 145 ℃ and 150 ℃ are found in CZ and TGT grown sapphire crystals respectively. With calculation by initial elevation method, thermoluminescence trap depths of two crystal samples are 1.15 eV and 1.05 eV, respectively.