Исследования морфологии роста водорастворимых кристаллов α-LiJO3. Влияние примесей на рост кристаллов α-LiJO3

Abstract

В ходе исследований разработана методика по оценке качества растворов на основе измерения «мертвой зоны» (∆Тм.з.) растворов -LiJO3. Величина «мертвой зоны» растворов является параметром, характеризующим содержание примесей в растворе, отравляющих грань призмы кристалла -LiJO3. По аналогии с измерением «мертвой зоны» для роста кристаллов группы KDP [1] для кристаллов -LiJO3 величина ∆Тм.з. также определяет пригодность растворов для роста [2]. Особый интерес представляют сравнительные исследования влияния ростовых параметров и примесей на кинетику роста граней и движения ступеней на двух разных кристаллах – KDP и -LiJO3. В работе представлены данные по действию некоторых примесей (Fe(IO3)2, AgIO3, CsOH, метилметакрилат) на рост грани (100) кристалла -LiJO3 = The growth technology and structural quality of crystals depend on the quality of raw material. The reason is that the presence of trace amounts of certain impurities in the raw material and, correspondingly, in the solution affects the growth kinetics of the (100) and (101) faces. In particular, some impurities significantly slow down the growth rate of prism faces and cause intersectorial stress, which is unacceptable for the production of large crystals using high-rate growth techniques. The ∆Тdz value, which determines the validity of solutions for growing α-LiIO3 single crystals, is an integral parameter of solution, characterizing the content of impurities distorting the prism face. This problem has become especially urgent in view of the studies on rapid growth of α-LiIO3 crystals (which are under way at the Institute of Applied Physics (Nizhny Novgorod)), because, by analogy with the rapid growth of KDP crystal, the ratio of the growth rates of (100) and (101) faces determines to a great extent the rapid growth of α-LiIO3 crystals. Lithium iodate (α-LiIO3) single crystal is a promising nonlinear optical material, which used for efficient laser radiation conversion in the visible and near-IR regions. A technique for measuring the “dead zone” (Тdz) of LiIO3 solutions has been developed; data on the impact of Fe(IO3)2, AgIO3, CsOH and methyl methacrylate on the growth of the (100) face of α-LiIO3 crystals have been presented; and the dependences of the nucleation and motion of single steps on the degree of super-saturation have been measured. It is shown that the Тdz value makes it possible to estimate the validity of solutions for growing α-LiIO3 crystals. The results of measuring the face growth rates and step velocities for KDP and α-LiIO3 crystals are compared