ICP与吸收光谱测定LiNbO3, Zn:LiNbO3晶体中Cr3+离子的分布及有效分凝系数

应用坩埚下降法生长了掺杂Cr与双掺杂Cr，Zn的LiNbO3晶体。测定了掺杂晶体不同部位的吸收系数。用电感耦合等离子体原子发射光谱(ICP)法测定了Cr离子在LN晶体中的浓度，并计算了Cr离子在LiNbO3晶体中的有效分凝系数。研究结果表明：在单掺杂Cr的LiNbO3晶体中，随着Cr^3 掺杂浓度从0．1增加到0．5mol％时，其有效分凝系数从3．75减少到2．49，Cr^3 离子在晶体中的浓度分布差异逐步减少；ZnO的掺入能有效地减少Cr^3 的分凝系数，然而ZnO掺杂浓度从3增加到6mol％时，其有效分凝系数且从1．85增加到2．25。可从ZnO组分对Cr离子的排斥作用及Zn离子在LN晶体中随掺杂数量变化的分凝现象解释了产生Cr离子浓度及有效分凝系数变化的原因。

Determination of Distribution and Effective Distribution Coefficient of Cr3+ in LiNbO3 Single Crystals Using UV/Visible Absorption Spectra and ICP

The LiNbO_3 crystals doped with Cr 3+ ion (Cr:LN) and co-doped with Cr 3+ and Zn ions (Zn:Cr:LN) were grown by the Bridgman method. The absorption coefficient and concentration of Cr 3+ in crystals were measured by UV/Visi ble spectra and inductively coupled plasma (ICP) spectrometry, respectively. The effective distribution coefficients (k) of Cr 3+ in the crystals were calculated. The results indicated that the k for Cr: LN crystal decreased f rom 3.75 to 2.49 as the incorporating concentration of Cr 3+ increased fr om 0.1 to 0.5 mol%; the introduction of ZnO in Cr:LN induced the reduction of k value effectively. However, the k value increased from 1.85 to 2.25 as the incorporating concentration of ZnO increased from 3 to 6 mol%. The varia tion of the k value was explained by the suppressing effect of ZnO on the in corporation of Cr 3+ ions and the distribution of Cr 3+ in LN.