Ni doping induced property enhancement in laser ablated BaSnO₃ films suitable for optoelectronic applications

Pulsed laser deposition is a straightforward approach for preparing films with superconducting to dielectric properties with atomic layer precision. The deep-seated mechanisms involved in the particle transport from target to substrate and subsequent film formation still need to be fully comprehended. This manuscript reports the property enhancement observed in laser ablated perovskite BaSnO₃ films with Ni doping. Films' crystallinity improvement is observed, and an intensity enhancement of 1150% is observed on 3 mol% Ni-doping. The optimum Ni-doping concentration in BaSnO₃ is found to be 3 mol%. Herein, Ni-doped BaSnO₃ films deposited by PLD showed an unusual increase in film thickness (i.e., from 615 nm in the pure film to 1317 nm in the film with 7 mol% Ni-doping as revealed by lateral SEM analysis and spectroscopic ellipsometry). We propose an "Induced Magnetic field-assisted Particle Convergence (IMPC)" effect for this superficial growth enhancement. The film's optical properties are modified with an increased nickel doping level, and the bandgap energy shows renormalization. All the films show excellent transmittance (80-90%) in the Vis.-NIR region. Hall-effect measurement reveals the increased carrier concentration by three orders (2.98 × 10¹¹ to 3.50 × 10¹⁴ cm^-3). In addition, the enhancement in mobility from 3.13 to 20.93 cm²V^-1s^-1 and a decrease in electrical resistivity by six orders (i.e., from 4.05 × 10⁹ to 1.13 × 10³ Ω cm) are observed on 7 mol% Ni doping. XPS measurements reveals that the Ba, Sn and Ni ions are at 2+, 4+ and 2+ oxidation states. Using spectroscopic ellipsometric method, we estimated the optical constants of the films, the refractive index, dielectric constant, and extinction coefficient show a normal dispersion behavior. The high crystallinity, high transmittance, suitable surface topography, and improved electrical performances of the Ni-doped BaSnO₃ films make them excellent candidates for optoelectronic devices and solar cells.