近化学计量比和同成分铌酸锂晶体中质子交换扩散系数的比较  

Comparison among Proton Exchange Diffusion Coefficients in Near-Stoichometric and Congruent Lithium Niobate Crystal

作　　者：贾晨阳 温旭杰 张维佳 华平壤[3] JIA Chenyang;WEN Xujie;ZHANG Weijia;HUA Pingrang(College of Electronic Information and Automation,Tianjin University of Science&Technology,Tianjin 300457,China;CETC Deqing Huaying Elecctronics Co.,Ltd.,Huzhou 313000,China;School of Precision Instrument and Optoelectronic Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津科技大学电子信息与自动化学院,天津300457 [2]中电科技德清华莹电子有限公司,湖州313000 [3]天津大学精密仪器与光电子工程学院,天津300072

出　　处：《天津科技大学学报》2022年第1期70-75,共6页Journal of Tianjin University of Science & Technology

基　　金：天津市重点研发计划科技支撑项目(19YFZCGX00140)。

摘　　要：利用不同条件下进行的质子交换和退火技术,在Z切近化学计量比和同成分铌酸锂晶体上制作了一系列平面光波导,并计算了相应的交换和退火扩散系数.实验结果表明,近化学计量比晶片中的退火扩散系数始终比同成分晶片中的值小,而两种材料中交换扩散系数的大小关系要根据交换液质量分数和交换温度而定.在交换液质量分数为0%、3%时,交换扩散系数随着温度的增加呈现增加的趋势;在交换温度225℃时,当交换液质量分数逐渐增大时,交换扩散系数迅速减小.通过对比近化学计量比和同成分晶片中交换和退火扩散系数的大小关系,总结出两种扩散机制:交换扩散机制和退火扩散机制.交换扩散机制工作原理是氢离子从外界溶液中不断进入晶体内部,同时锂离子则源源不断地从晶体向溶液中逸出,让出来Li空位逐渐被氢离子占据.退火扩散机制工作原理是没有离子进入或逸出晶体的情况,氢离子只是从晶体表面往内部扩散,与典型的铌酸锂晶体中的钛扩散过程相似,氢离子的运行需要借助Li空位.质子交换过程是这两种扩散机制共同作用下的结果.本文工作为制作高质量的周期性极化铌酸锂波导开辟了一条新的路径.A series of planar optical waveguides were fabricated on Z-cut stoichiometric LiNbO_(3) crystals by proton exchange and annealing techniques under different conditions,and the corresponding exchange and annealing diffusion coefficients were calculated.The experimental results show that the annealing diffusion coefficient in the near stoichiometric wafer was always smaller than that in the same composition wafer,and the relationship between the exchange diffusion coefficient in the two materials depended on the mass fraction of the exchange solution and the exchange temperature.When the mass fraction of exchange solution was 0%and 3%,the exchange diffusion coefficient increased with the increase of temperature;When the exchange temperature was 225℃,the exchange diffusion coefficient decreased rapidly when the exchange solution mass fraction increased gradually.By comparing the near stoichiometry and the relationship between the exchange and annealing diffusion coefficients in the same composition wafer,two diffusion mechanisms are summarized:exchange diffusion mechanism and annealing diffusion mechanism.The working principle of exchange diffusion mechanism is that hydrogen ions continuously enter the crystal from the external solution,while lithium ions continuously escape from the crystal to the solution,so that the Li vacancy is gradually occupied by H ions.The working principle of annealing diffusion mechanism is that no ions enter or escape from the crystal,and H ions only diffuse from the crystal surface to the inside,which is similar to the diffusion process of titanium in typical lithium niobate crystal.The operation of H ions needs the help of Li vacancy.The proton exchange process is the result of these two diffusion mechanisms.This study opens a new way to fabricate high quality periodically poled lithium niobate waveguides.

关 键 词：质子交换 铌酸锂 扩散系数 近化学计量比 同成分 

分 类 号：TN252[电子电信—物理电子学]