Modulating the Properties of SnO₂ Thin Film by Post-Deposition UV-Ozone Treatment

Tin(IV) oxide (SnO₂) is a metal oxide renowned for its excellent optoelectronic properties. With the use of simple post-processing methods, the characteristics of SnO₂ may be easily modified. In the current work, SnO₂ thin films were prepared using the spray pyrolysis technique and were subjected to post-UV-ozone (UVO) treatment for different durations. Characterization techniques including x-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, UV–visible spectroscopy, and photoluminescence spectroscopy were employed to assess the effects of UVO treatment. It was found that UVO treatment had no significant impact on the film's structural characteristics. However, after exposure to UVO, the bandgap was seen to decrease from 3.04 eV to 2.84 eV. Also, photoluminescence investigations revealed that UVO treatment increased the defects in the films with a decrease in the ratio between band-to-band emission and defect emissions. The results indicate that UVO treatment is an effective strategy for tuning the optical properties of SnO₂ thin films by precisely managing the bandgap.