ZENG Xian-lin, WANG Jin-hao, XIA Hai-ping, ZHANG Jian-li, SONG Hong-wei, ZHANG Jia-hua, YAO Lian-zeng. Absorption Spectra of LiNbO<sub>3</sub>, Fe:LiNbO<sub>3</sub>, and Zn:Fe:LiNbO<sub>3</sub> Crystals Grown by Bridgman Method[J]. Chinese Journal of Luminescence, 2004,25(4): 435-440
ZENG Xian-lin, WANG Jin-hao, XIA Hai-ping, ZHANG Jian-li, SONG Hong-wei, ZHANG Jia-hua, YAO Lian-zeng. Absorption Spectra of LiNbO<sub>3</sub>, Fe:LiNbO<sub>3</sub>, and Zn:Fe:LiNbO<sub>3</sub> Crystals Grown by Bridgman Method[J]. Chinese Journal of Luminescence, 2004,25(4): 435-440DOI:
坩埚下降法生长的LiNbO3,Fe:LiNbO3,Zn:Fe:LiNbO3单晶的吸收光谱特性
摘要
用紫外可见光谱(UV/VisibleSpectra)测试并研究了坩埚下降法生长的LiNbO
3
、Fe:LiNbO
3
以及Zn:Fe:LiNbO
3
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:LiNbO
3
单晶沿晶体生长方向
其紫外吸收边向长波方向移动
且在350~450nm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:LiNbO
3
单晶中观察到Fe
2+
离子在480nm附近的特征吸收峰
并发现沿生长方向
Fe
2+
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:LiNbO
3
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。Fe
2+
离子在Zn:Fe:LiNbO
3
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:LiNbO
3
单晶中
Fe
2+
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Zn
2+
抑制Fe
2+
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Fe
2+
离子在晶体中的浓度分布的影响作了分析。
Abstract
The UV/visible absorption spectra of LiNbO
3
Fe:LiNbO
3
and Zn:Fe:LiNbO
3
crystals grown by Bridgman method were measured and investigated.The characteristics of the absorption were explained
and the effects of growth processing on the absorption spectra were also discussed.The results indicate that the absorption edge of lithium niobate shifts to longer wavelength
and the absorption intensity in the range of 350
4
50nm band increases along the direction of crystal growth.The reason of above causes is lacking of lithium composition in crystal
which resulted from the volatilization and segregation of lithium in growth period.A band at 480nm which attributed to Fe
2+
ion absorption was observed in Fe:LiNbO
3
crystal
and it was found that the intensity of the band increases along the growth direction
which means the increase of Fe
2+
ion along the direction
and the incorporation of Fe in LiNbO
3
resulted in a red shift of absorption edge.However
the concentration of Fe
2+
ion in the obtained crystal increases obviously compared with that of Fe:LiNbO
3
in same quantity of Fe dopant
which was quite different from that of crystal grown by the Czochralski method.When ZnO in
w
(ZnO)=1.7% was doped
a blue shift of absorption edge was observed
but a slightly red shift for
w
(ZnO)=3.4% ZnO.Among Fe-doped and Zn/Fe co-doped LiNbO
3
crystals
1.7% ZnO doped Fe:LiNbO
3
has biggest change of Fe
2+
ion mass fraction from bottom to top part of crystal.A stronger suppressing effect on Fe
2+
concentration in Zn:Fe:LiNbO
3
single crystals resulted from doping
w
(ZnO)=1.7% than
w
(ZnO)=3.4%.The effect of the special growth technology on the Fe