碱金属钽铌酸盐薄膜的可控生长与光学特性研究

发布时间：2018-03-29 13:53

本文选题：KTN薄膜　切入点：脉冲激光沉积技术　出处：《哈尔滨理工大学》2017年硕士论文

【摘要】：碱金属钽铌酸盐光电功能材料以其显著的电光性能在光电信息处理领域等具有较大的应用潜力。相对于体块材料,薄膜形式可以大幅度降低材料的电光调制电压,促进纳秒、亚纳秒量级光开关的实用化进程。因此,对碱金属钽铌酸盐薄膜的研究有着重要的理论与实用意义。本文针对钽铌酸盐材料薄膜化问题展开,制备了纯KLTN电光薄膜并对其实现可控生长,以及对薄膜的基本光学性能和薄膜中的光传输特性进行了研究。利用脉冲激光沉积(PLD)技术成功制备了钙钛矿相的KTa_(0.5)Nb_(0.5)O_3(KTN50)、KTa_(0.65)Nb_(0.35)O_3(KTN65)和K_(0.95)Li_(0.05)Ta_(0.65)Nb_(0.35)O_3(KLTN65)薄膜,从实验方面探索了薄膜的生长规律,得到了薄膜的最佳生长条件。结构及微观形貌表征表明,薄膜在(h00)方向取向度高达94.6%,晶粒尺寸大约50-100nm,且结晶质量良好。针对薄膜生长输运过程中粒子偏离化学计量比造成杂相产生的情况,主要研究了PLD法制备KTN薄膜等离子体羽辉的传输特性,得到了等离子体浓度的空间和时间分布特性。并在此基础上,研究了K、Nb和Ta原子的沉积规律,为钽铌基薄膜的可控生长提供了支持。利用紫外-可见光分光光度计、椭偏仪和Z扫描等分析了KTN薄膜的透射和吸收光谱、折射率等基本光学性能。根据光谱特性计算得到薄膜厚度参数,并解释了薄膜光学禁带展宽的原因;基于薄膜的折射率色散特性,得出在Pt(111)/Ti/SiO_2/Si基片上生长的钽铌酸盐薄膜的折射率方程参数;由薄膜的三阶非线性光学特性,研究得到其非线性折射系数为-6.59×10~(-10)cm~2/W,表明薄膜在波长为532nm、脉宽为8ns、光功率密度为0.48GW/cm~2激光下具有自散焦特性。另外,为了探索KTN薄膜在光学器件领域的潜在应用,进一步研究了KTN/MgO和ITO/KTN/Pt平面波导中的光传输特性,通过频域分析和边界模式分析,得到了KTN平面波导的传播模式,并研究了不同尺寸薄膜TE模式的光传输效率,发现薄膜厚度200-500nm时波长为632.8nm的光具有较高的传输效率和较低的传输损耗。
[Abstract]:The alkali tantalum niobate photoelectric functional materials have great application potential in the field of optoelectronic information processing due to their remarkable electro-optic properties. Compared with bulk materials, the film form can greatly reduce the electro-optic modulation voltage of the materials and promote nanoseconds. Therefore, the study of tantalum niobate thin films has important theoretical and practical significance. In this paper, the thinning of tantalum niobate materials is discussed. Pure KLTN electro-optic thin films have been prepared and their controllable growth has been studied. The basic optical properties of the films and the optical transmission characteristics in the films have been studied. By using the pulsed laser deposition (PLD) technique, the KTaS 0.5NbS / KTN50 / KTa0.65Nb 0.35Nb / 0.35Nb / KTN65 and 0.65NbS / 0.65NbS / 0.65NbS / 0.35NbS / 0.35NbS / 0.65NbS / 0.35Nb / 0.65Nb / T / 0.35Nb / T / 0.35NT / KTN65T thin films of perovskite phase have been successfully prepared by using pulsed laser deposition (PLD) technique. The optimum growth conditions of the films were obtained, and the structure and microstructure of the films were characterized. The orientation degree of the film is as high as 94.6, the grain size is about 50-100 nm, and the crystal quality is good. The transport characteristics of plasma plume of KTN thin films prepared by PLD method were studied, and the spatial and temporal distribution of plasma concentration were obtained. On the basis of this, the deposition rules of Knb and Ta atoms were studied. It provides support for the controllable growth of tantalum and niobium thin films. The transmission and absorption spectra of KTN thin films are analyzed by UV-Vis spectrophotometer, ellipsometry and Z-scan. Basic optical properties such as refractive index. The thickness parameters of thin films are calculated according to their spectral characteristics, and the reasons for the broadening of optical bandgap are explained. The refractive index equation parameters of tantalum niobate thin films grown on Pt(111)/Ti/SiO_2/Si substrates are obtained. The nonlinear refraction coefficient of the film is -6.59 脳 10 ~ (-10) ~ (-1) cm ~ (2 / W), which shows that the film has self-defocusing characteristics at wavelength of 532 nm, pulse width of 8 nm and optical power density of 0.48GW/cm~2 laser. In addition, in order to explore the potential applications of KTN thin films in optical devices, The propagation characteristics of KTN/MgO and ITO/KTN/Pt planar waveguides are further studied. The propagation modes of KTN planar waveguides are obtained by frequency domain analysis and boundary mode analysis, and the optical transmission efficiency of te modes with different sizes is studied. It is found that the light with the wavelength of 632.8nm has higher transmission efficiency and lower transmission loss when the film thickness is 200-500nm.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O484

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