Characterization of deep level defects in Tl6I4S single crystals by photo-induced current transient spectroscopy

Abstract

Defect levels in semi-insulating Tl6I4S single crystals grown by the horizontal Bridgman technique have been characterized using photo-induced current transient spectroscopy (PICTS). These measurements revealed six electron traps located at (0.059 ± 0.007), (0.13 ± 0.012), (0.31 ± 0.074), (0.39 ± 0.019), (0.62 ± 0.110), and (0.597 ± 0.105). These defect levels are attributed to vacancies (VI, VS) and antisite defects (IS, TlS, TlI) upon comparison to calculations of native defect energy levels using density functional theory and defects recently reported from photoluminescence and photoconductivity measurements.