Effect of Li Doping on Structural, Optical, and Optoelectrical Characteristics of ZnSnO3 Thin Films Prepared by Nebulizer Spray Pyrolysis

In this work, ZnSnO3 (ZTO3) and Li-doped ZTO3 thin films were synthesized on glass slides by a cost-effective nebulizer spray pyrolysis procedure. The X-ray diffraction analysis revealed that the ZTO3 and Li-doped ZTO3 thin films possessed a rhombohedral structure. The structural indices (grain size, dislocation density, lattice strain) of the ZTO3 and Li-doped ZTO3 thin films were computed. The morphology characteristics of the ZTO3 and Li-doped ZTO3 thin films were observed by field emission scanning electron microscopy. The inspected films display uniform and homogeneous surfaces. The optical transmittance, T, and reflectance, R, of the ZTO3 and Li-doped ZTO3 thin films were recorded using a double-beam spectrophotometer to investigate the optical characteristics of these layers. The refractive index of the ZTO3 and Li-doped ZTO3 thin films was enhanced via the Li content increase. Moreover, Tauc’s plots demonstrated that the energy gap of the ZTO3 and Li-doped ZTO3 thin films was reduced from 3.85 eV to 3.08 eV by boosting the Li doping content. Moreover, the increase in Li content produces an enhancement in the optoelectrical indices (optical resistivity, optical carrier concentration, optical mobility, plasms frequency, and optical conductivity) of the ZTO3 and Li-doped ZTO3 thin films. The nonlinear optical indices of the ZTO3 and Li-doped ZTO3 thin films were deduced, and it was noted that Li content boosted the nonlinear optical indices of these layers. All the ZTO3 and Li-doped ZTO3 thin films displayed n-type semiconducting properties by the hot probe equipment.