Unsteady Growth ofBaB2O4Single Crystal from High-Temperature Solution

[摘要] Two-dimensional growth ofBaB2O4single crystal from high-temperature solution was performed, and the motionof solid-liquid interface was observed in real time by differential interference microscopy. Results show that the solid-liquidinterface exhibits the morphology of a vicinal face where steps with height of several microns are observed. Themeasurements of growth rate V and step propagating velocityυshow that both V andυfluctuate by up to 40∼50% oftheir average values, respectively, under constant external conditions. Such intrinsic fluctuations with time interval of theorder of one second is mainly the result of step bunching, which has been confirmed by the gradual decrease of stepspacing when approaching the edge of the growing interface. Besides above fluctuations, a longer-period oscillation ofV (period interval of 4∼5 seconds) is obtained for relatively rapid growth, which is triggered by the periodical alteration of steppropagating directions.

[学科分类] 材料工程