Tuning znO with Y and in dopants: DFT analysis of mechanical, electronic, and optical properties

This study investigates how yttrium (Y) and indium (In) substitutional doping tailors ZnO using density functional theory (DFT) in CASTEP within Materials Studio. A 2 × 2 × 2 supercell with Zn-site substitution at two loadings was optimized; we computed band structure/DOS, frequency-dependent optics (including dielectric function and conductivity), elastic constants, thermal stability, and simulated X-ray diffraction. Undoped and moderate dopings are elastically stable; the highest Y case is unstable. XRD retains the phase; Y causes stronger peak broadening/ 2 θ shifts than In. Electronically, moderate Y closes the gap, higher Y yields a narrow gap with high DOS; In is metallic at both loadings. Optically, Y red-shifts and strengthens low-energy response, whereas In shows stronger free-carrier reflectivity. These complementary trends guide dopant selection for optoelectronics.