Understanding SILAR-Grown SnO2 thin films: how altered deposition cycle numbers/film thickness influence characterization

In this study, the morphological, structural, chemical and optical assets of SnO₂ thin films with varying thicknesses, grown by the Successive Ionic Layer Adsorption and Reaction (SILAR) technique, were systematically investigated. X-ray diffraction (XRD) analysis validated the polycrystalline nature of the films with a tetragonal rutile structure, and the crystallite size was observed to decrease with decreasing film thickness. Energy-dispersive X-ray analysis (EDAX) provided insights into the elemental composition, indicating high purity of SnO₂ films. Raman spectroscopy revealed characteristic peaks corresponding to the Sn-O vibrations. Scanning electron microscopy (SEM) images showed a uniform surface morphology with a clear dependence on film thickness, with thinner films exhibiting smaller grain sizes. Optical measurements, including absorbance and transmittance, were used to determine the films’ band gap, which exhibited a shift with thickness variation, indicating quantum confinement effects. Photoluminescence (PL) spectra revealed significant defect-related emission peaks, which intensified as the thickness decreased. X-ray photoelectron spectroscopy (XPS) was implemented to analyze the chemical states of the constituent elements, confirming the presence of both Sn⁴⁺ and O²⁻ in all films. This comprehensive analysis demonstrates how varying film thickness influences the material properties of SnO₂ samples, supplying noteworthy insights for their potential utilizations in optoelectronic devices, sensors, and coatings.