The study of structural, electronic, and optical properties of Ti- substituted CaZr1-xTix S3 (x=0.00, 0.25, 0.50, 0.75, and 1.00) for optoelectronic applications: Using GGA and GGA+U

Abstract

In this study, we examined an orthorhombic phase, CaZr1−xTixS3(x = 0.00, 0.25, 0.50, 0.75, 1.00) (space group Pnma (62)) with B-site Zr substituted by Ti (25%Ti, 50%Ti, 75%Ti) using density functional theory, with the help of a plane wave ultra-soft Pseudopotentials (PW-USPPs) in a generalized gradient approximation (GGA) and with Hubbard onsite correction (DFT + U). The equilibrium state properties such as lattice parameters, unit cell volume, bulk modulus, and its derivative are calculated. The change in concentration of Ti affects the bulk modulus and its derivatives which results in variations in the compressibility and hardness of the material. It is found that CaZr1−xTixS3 with different concentrations of Ti shows a tuned direct band gap located at Γ-symmetry point. The band gap values decrease as impurity concentration increases. The band gap values of CaZr1−xTixS3 (for 0.25, 0.50, 0.75, and 1.00) lie in the optimal energy range (1.0–1.6 eV). Moreover, it is observed that CaZr1−xTixS3(x = 0.00, 0.25, 0.50, 0.75, 1.00) has a good optical response from the visible to ultraviolet energy range. The results predict these materials may be used in solar cell applications and optoelectronic devices.