From discussing the factors that influence the quality of the single - crystal , a positive method using the floating - boat method from the british mr corp . to control the diameter of the single - crystal was determined , and produced the highest quality low epd single - crystals international 该实验讨论了各种因素对拉制磷化镓单晶的影响。并确定了一套较优越的拉制方法，制备出了国际上现阶段所能达到的最高水平的低位错单晶。
2 . the optical transmission spectra of batio3 thin films annealed at different temperatures on fused quartz substrates are measured . the bandgap energies calculated from their optical transmission spectra are larger than that of single crystals reported in the literatures , whereas for poor - crystallized films with lower annealing temperature , their bandgap energy values are much larger than that of single crystals 发现batio3多晶薄膜的光学带隙大于文献报导的单晶薄膜的光学带隙,对于结晶性好的薄膜,其光学带隙接近于单晶值,退火温度越低,结晶性越差,与单晶的光学带隙相差越大。
The crystals of znse monocrystal grown via physical vapor transport ( pvt ) results higher cost and complicated procedures under congruent sublimation condition . therefore , a new chemical vapor transport ( cvt ) method was designed to grow znse crystals in our investigations . the compound ( nh4 ) 3zncl5 was employed as a transport agent in cvt method for the first time 受znse过窄的一致升华范围限制，物理气相输运( pvt ， physicalvaportransport )技术生长znse单晶需要复杂的程序，因此我们选择化学气相输运( cvt ， chemicalvaportransport )技术作为生长znse单晶的主要技术，并作了一定的改进。
We have developed the theory of boundary shielding approximation of electric polarization , from which the values of spontaneous polarization of some typical ferroelectric materials can be derived . the shielded charges in ferroelectricity are in the state of surface bound polaron - dipole whose creation and annihilation must span a potential barrier . by introducing statistical method , four types of typical electric hysteresis loops of some common crystals and ceramics have been given , which are well consistent with the experimental results 利用电极化的边界屏蔽近似，可计算出一些典型铁电单晶的自发极化强度.铁电屏蔽电荷处于表面束缚极化子偶状态,其产生和湮没要跨越位垒.由统计方法给出的一些常见晶体和陶瓷的四种典型电滞回线形状，和实验观察到的结果一致
The study on the structure and micromorphology of two znse monocrystal indicated that the growth mechanism of znse monocrystal via vapor is two - dimension nucleation and growth , and ( 111 ) face is the mainly appearing face . the results provide an important experimental evidence for the growth theory of singular face . ultrafast nonlinear optical properties of as - grown znse single crystals were investigated by femtosecond pulses 两种方法生长znse体单晶的结构和形貌研究表明，在输运剂zn伽场) 3c15的存在和本文实验条件下， cvt气相生长znse的机理主要为二维成核与生长机理， ( 111 )面为主要生长晶面，该结果为立方晶体的奇异面生长理论提供了重要的实验证据。
Because of its brilliant application prospects and the difficulties in single crystal growth , the growth technique and properties of znse single crystals have attracted mach attention and have become the most active areas in znse semiconductor research . in this thesis , we present our work on the optical and electronic property characterizations , as well as the growth methods 本文工作重点是探索制备工艺简单、成本低、操作简便的znse单晶生长新方法，获得化学计量比接近1 ： 1的、具高结晶质量的znse体单晶，并在此基础上对生长的znse单晶的结构特点、光学和电学特性进行进一步研究。
Accordingly , a new framework , which provides a common scheme for the numerical simulation on the macroscopic behavior of ferroelectrics though multi - scale analysis on the coupled thermo - electrics - mechanical behavior of multiphase in heterogeneous material , is induced to construct the effective constitutive equation of multiphase . in chapter four , based on the law of domain nucleation and domain wall motion of 1800 domain switching , a new scheme of domain switching and numerical simulation approach is put forward on the foundation of thermodynamics . driving traction , nucleation criterion , velocity of domain wall motion , kinetic relation and rate of domain switching in a single grain are given 第四章以铁电体1800畴变的过程中形核规律和畴界运动规律的实验观察结果为基础，根据热力学理论建立铁电体畴变的理论框架和数值模拟方法；给出了单畴内畴变驱动力、新畴形核准则、畴界运动速度公式、畴变动力学的表达式，单晶的畴变速率公式；用细观力学的观点给出了对多晶铁电体多场耦合的有效性质进行包含畴变速率影响的多尺度分析方法。
In this project we use etching method x - ray transmission and tem observe and study the form mechanism of cell structure and linear structure ; use sem observe cell structure directly and evaluate effect to the electrical properties of substrate ; at last , use high resolution tem and eds to observe and identify the nature of microdefects 发现几乎所有高位错密度的si - gaas单晶的表层都具有网络状胞状结构或系属结构，首次对该胞状结构和系属结构的形成机制进行了研究；直接观察微缺陷，配合eds (能量色散谱)鉴定si - gaas中微缺陷的物理本质，同时分析其产生原因，讨论与位错的相互作用。
