OPTICAL PROPERTIES of the TlSbP2Se6 SINGLE CRYSTALL

The scientific interest in TlSbP2Se6 compound is due to a number of factors. Firstly, this compound is characterized by congruent melting behavior, which allows obtaining high-quality bulk single crystals by the method of directional crystallization using the Bridgman technique. Secondly, it is characterized by an acentric 2 D layered structure. Previous studies of TlSbP2Se6 single crystals were limited to optimizing the conditions for growing single crystals, refinig its crystal structure, determining its qualitative and quantitative composition, determining the optical transparency region, and evaluating its physical characteristics using quantum chemical calculations. The purpose of this study was to compare the calculated values of the band gap of TlSbP2Se6 with those experimentally determined by the results of the optical absorption edge study. We prepared plane-parallel samples of single-crystal TlSbP2Se6 along the cleavage plane. The width of the band gap was determined from the transmission spectra using the Tauc method. It was established that the compound TlSbP2Se6 belongs to direct-band semiconductors with a band gap of 1.81 eV. The values calculated by the Becke-Johnson method using the modified functional with the Hubbard parameter and spin-orbit interaction (TB-mBJ+U+SO) and without (mBJ) were the closest to the experimental band gap.