Characterization of Cu-rich and Zn-poor Cu₂ZnSnS₄ single crystal grown by vertical Bridgman technique

To date, although a number of studies have focused on understanding the fundamental properties of Cu-poor/Zn-rich Cu₂ZnSnS₄ (CZTS) single crystals, little attention has been paid to investigate the physical properties of those with a Cu-rich / Zn-poor chemical composition. Therefore, in this study, the structural and electrical properties of Cu-rich/Zn-poor CZTS single crystal grown by the Bridgman technique have been studied in order to fill this gap in literature. XRD and Raman findings confirm the growth of CZTS single crystal having a kesterite phase without secondary phases. Hall and temperature dependent conductivity measurements reveal the presence of V_Cu and Cu_Zn antisite point defects in CZTS during the growth stage with thermal activation energies of 15 meV and ∼100 meV, respectively. Hall mobility, resistivity and hole carrier concentration values at room temperature were found to be 1.2 cm²/V.s, 16.2 Ω.cm and 3.1 × 10¹⁷ cm⁻³, respectively.