BANDGAP RENORMALIZATION AND PROPERTY ENHANCEMENT DUE TO Fe-DOPING IN LASER ABLATED BaSnO3 FILMS

Nano-structured materials exhibit exciting physical and chemical behaviors different from their bulk counterpart, and their exotic behaviors are due to their increased relative surface area and spatial confinement of charge carriers. Pulsed laser deposition (PLD) is a straightforward, simple, thin film preparation approach with which one can deposit films with atomic layer precision. Using the PLD, we deposited BaSn1-xFexO3 films with x = 0, 0.01, 0.02, 0.3, 0.05 and 0.07 mol% and investigated their structural, microstructural, and optical properties in detail. We observed an increase in XRD intensity and a reduction in FWHM in the most preferred direction of crystalline growth <110> with enhanced iron-doping levels, and these suggest the crystallinity enhancement in the films. We observed an unprecedented film thickness enhancement with Fe-doping level enhancement (from 640 nm for undoped film to 1,158 nm for seven mol% Fe-doped film). We proposed this to induced Magnetic field-assisted Particle Convergence effect. FESEM and AFM analysis shows a pin-hole-free uniform surface for 5 mol% Fe-doped film. Films exhibit high transmittance values (71 to 91% range), even under heavy doping levels, revealing their exemplary optical quality. We have observed bandgap renormalization in films under Fe-doping (Eg = 3.18 eV for pristine film and Eg = 2.72 eV for 7 mol% Fe-doped film). XPS analysis of the films suggests +3, +2, and +4 oxidation states for the Fe, Ba, and Sn ions. The high crystalline nature, high transmittance, suitable bandgap values, and good surface morphology of the Fe:BaSnO3 films make them suitable for optoelectronic applications.