Interface Diagnostics:\nEquivalent Circuit Characterization\nfor a Growing Bulk Single Crystal

Despite the Czochralski technology having been commonly\nused for\nmanufacturing bulk single crystals, crystal quality and production\nare still limited by the insufficient understanding of the crystal-melt\ninterface. Herein, we propose a novel perspective on the voltammetric\ncharacteristics of an equivalent circuit model to reveal a growing\nboule. Specifically, by elucidating the interface electromotive force\nduring lithium niobate crystal growth, we find the nonlinear conduction\nbehavior at the crystal-melt interface, representing the characteristic\nof a PN junction. Further regarding this interface as a rectifier\ndiode with parasitic resistance, the volt-ampere curves will draw\nabundant crystal growth information <i>in situ</i>. For\nexample, the real-time cyclic voltammetry curves are highly consistent\nwith the circuit simulations, whose series resistance well predicts\nthe actual length of the as-grown crystal. More importantly, this\nequivalent circuit model establishes a simple but effective perspective\nfor revealing the nature of the growth system, encompassing the kinetics\nof high-temperature phase transition and the thermodynamics of quantitative\ncomposition control.