Role of temperature oscillation in growth of large-grain CdZnTe single crystal by traveling heater method

Abstract

Self-nucleation in CdZnTe crystal growth remains a significant challenge, despite numerous attempts to achieve large-grain single crystals by restricting multi-nucleation during growth process using the traveling heater method. In this study, we present a novel approach to achieve large-grain CdZnTe single crystals by introducing temperature oscillations above the crystallization temperature during the growth process. This method effectively suppresses secondary nucleation and promotes the preferential selection of a single grain during early stage of growth as well as along the growth axis, by reducing multi-nucleation. By adjusting the amplitude and the number of temperature oscillations, we have successfully grown CdZnTe single crystals with dimensions of 20 mm in diameter and 60 mm in length. The resulting crystals exhibited excellent compositional homogeneity, with a nearly constant resistivity of ∼ 10⁹ Ω·cm and Te inclusions smaller than 15 µm along the growth axis. Additionally, the crystal elements were of detector grade achieving an energy resolution of 4.5 % for gamma radiation at 662 keV from a ¹³⁷Cs source in a quasi-hemispherical geometry. This study highlights the critical role of temperature oscillations in controlling secondary nucleation and promoting the formation of large-grain single crystals.