【作者】 张晓红；

【导师】 常新安；

【作者基本信息】 北京工业大学 ， 材料学， 2001， 硕士

【摘要】 本文主要对Zr⁴⁺∶KTP晶体和Ce⁴⁺∶KTP晶体的生长方法、生长形态和完整性、晶体结构及相关性能进行研究。 采用高温溶液法，我们先后生长出了二十余块掺质离子种类不同，掺质浓度不同的掺质KTP晶体。用x射线单晶衍射仪测得掺质晶体的晶胞参数与纯KTP晶体的相比，变化不大，同时用同步辐射形貌术对掺质晶体进行研究得到了与纯KTP完全相同的透射同步辐射Laue斑点花样，这都说明掺Zr⁴⁺和Ce⁴⁺没有改变KTP晶体的结构。所有的Zr⁴⁺∶KTP和Ce⁴⁺∶KTP晶体与纯KTP一样，都是由｛100｝｛011｝｛201｝｛110｝几个单形所组成的聚形。但掺质改变了晶面生长习性，主要表现在｛100｝面族变大，｛110｝面族变小，a向相对尺寸变小。掺Zr⁴⁺对其影响尤其明显，晶体a向很薄，外形呈薄片状。Ce⁴⁺∶KTP晶体与纯KTP的形态比较相近。 通过光学显微镜或直接观察到掺质晶体上的包裹体、生长条纹、云层、台阶等宏观生长缺陷。同时，运用同步辐射白光形貌术观察到晶体内部有生长扇形界、生长条纹、位错等微观缺陷，发现掺质使KTP晶体的完整性降低了，特别是Zr⁴⁺∶KTP晶体内部的晶体缺陷密度增大，其完整性不如Ce⁴⁺∶KTP。 运用等离子发射光谱（ICP）测定了掺质离子在晶体中的实际浓度，发现半径较大的Ce⁴⁺，很难进入KTP晶体中占据Ti⁴⁺格位，其分配系数较小，只有1.25×10^-3～6.78×10^-3。半径与Ti⁴⁺相近的Zr⁴⁺，容易进入晶体取代Ti⁴⁺，其分配系数较大，大约为0.0118～0.0386。另外发现，分配系数有随掺质浓度增大而减小的趋势。 分别对Ce⁴⁺∶KTP，Zr⁴⁺∶KTP和KTP三种晶体的透过曲线、倍频效应、a向电导率等性能进行了相关测试。测试结果表明：掺Ce⁴⁺能提高KTP晶体的透过率和透过范围，而掺Zr⁴⁺对晶体透过率的影响较小，其透过曲线与纯KTP的在紫外到近红外波长范围内几乎重合；Zr⁴⁺和Ce⁴⁺的掺入有助于晶体倍频效应的增强，且Ce⁴⁺的掺入后晶体倍频效应增强更明显一些；掺Zr⁴⁺使KTP晶体的a向电导率降低，掺Ce⁴⁺不改变晶体的a向电导率。更多还原

【Abstract】 In this paper, efforts have been made to study the crystal growth, crystal morphology and integrity, crystal structure and relevant properties of Zr4+-doped and Ce4+-doped KTP crystal. More than twenty doped KTP crystals with different dopant and different doping concentration were grown by flux method. The cell parameters of the crystals were determined by x-ray single crystal diffractometer and change little in comparison with the pure one. Also, the Laue spot of the doped KTP crystals was simulated and is same to the pure one. All Zr4+doped and Ce4+-doped KTP crystals comprise the same faces as the pure one. But all the doping modifies the crystal morphology, and a-axis size of the doped crystal turns thinner, especially fOr .the Zr4+-doped KTP crystals. The Zri+-doped KTP crystal is plate-like and the Morphology of Ce4+-doped is more like the pure KTP crystal. Some macroscopical defects in doped KTP crystals have been observed directly or by optical microscope, such as inclusions, cracks and growth steps. Meantime some microscopical defects have been found by White-beam Synchrotron Radiation topography, such as the growth sector boundary and growth stripes. Thus, the integrity of the crystals was destroyed. There is more defects density in Zr4+-doped KTP crystals than in Ce4+- doped KTP crystals, so the integrity of Ce4+-doped KTP crystals is better than Zr4+-doped KTP crystals. The distribution coefficients of the doping ions in the growth system have been calculated after the measurement of the dopant concentration in crystals by ICP. Because of the larger ion radius than Ti4+, Ce4+is hard to enter the inner structure for substituting Ti4+ and the distribution coefficient is rather low. Zr4+, which is almost similar to Ti4+ in size, is easy to enter the inner structure and substitute Ti4+., thus obtaining a large distribution coefficient. The results show that the distribution coefficient decreases with the increase of the doping concentration.. The transmission curve, doubling effect and a-axis conductivity were tested by relevant methods. The results show: Ce4+ doping can improve the transmission of KTP crystal while Zr4+ doping have no influence on it; Ce4+and/ or Zr4+doping can increase the doubling effect and Ce4+ doping has more influence than Zr4+ doping on it; Zr4+ doping can make the a-axis conductivity decrease and Ce4+ doping has no any influence on it.更多还原