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用紫外可见光谱 (UV/VisibleSpectra)测试并研究了坩埚下降法生长的LiNbO3 、Fe∶LiNbO3 ,以及Zn∶Fe∶LiN bO3 晶体的吸收特性。分析了产生这些吸收特性的原因以及与工艺生长方法的内在联系。研究结果表明 :LiNbO3 单晶沿晶体生长方向 ,其紫外吸收边向长波方向移动 ,且在 35 0～ 4 5 0nm波段的吸收也逐渐增大 ,这是由于Li的分凝与挥发 ,逐渐产生缺锂所造成的 ;在Fe∶LiNbO3 单晶中观察到Fe2 + 离子在 4 80nm附近的特征吸收峰 ,并发现沿生长方向 ,Fe2 + 离子的浓度逐渐增加 ,这与提拉法生长得到的晶体不同 ;在Fe∶LiNbO3 单晶中掺入质量分数为 1.7%ZnO后 ,吸收边位置发生蓝移 ,而掺杂质量分数达到 3.4 %时 ,观察到有红移现象。Fe2 + 离子在Zn∶Fe∶LiNbO3 单晶中的浓度与ZnO掺杂量有密切关系。在掺杂质量分数 1.7%ZnO的Fe∶LiNbO3 单晶中 ,Fe2 + 离子从底部到顶部的浓度变化比在掺杂质量分数 3.4 %ZnO晶体中大 ,这是由于Zn2 + 抑制Fe2 + 离子进入Li位的能力随掺杂量的增加而逐渐减弱造成的。就该下降法工艺技术对Fe2 + 离子在晶体中的浓度分布的影响作了分析
The absorption characteristics of LiNbO3, Fe: LiNbO3, and Zn: Fe: LiNbO3 crystals grown by the crucible descent method were investigated by UV / Visible Spectra. The reasons for the occurrence of these absorption characteristics and the inherent relationship with the process growth were analyzed. The results show that the absorption of the LiNbO3 single crystal along the crystal growth direction shifts to the long wave direction, and the absorption in the 35 0-4 500 nm band also increases gradually, which is due to the segregation and volatilization of Li, Lithium; the characteristic absorption peak of Fe2 + ions in the vicinity of 4 80 nm was observed in Fe: LiNbO3 single crystal and found that the concentration of Fe2 + ions gradually increased along the growth direction, which was different from the crystal obtained by the Czochralski method ; In the Fe: LiNbO3 single crystal doped with 1.7% ZnO mass fraction, the absorption edge position blue shift occurs, while the doped mass fraction of 3.4%, the observed red shift phenomenon. The concentration of Fe2 + ions in Zn: Fe: LiNbO3 single crystal is closely related to the amount of ZnO doping. In the Fe: LiNbO3 single crystal doped with 1.7% ZnO, the concentration of Fe2 + from bottom to top is larger than that of 3.4% ZnO, which is because Zn2 + inhibits the entry of Fe2 + into Li Bit with the doping capacity increases gradually diminished caused. The influence of the descending process technology on the concentration distribution of Fe2 + ions in the crystal was analyzed