Effect of cobalt on the structural, morphological, optical, and electrical properties of SnO2 thin films prepared by dip coating technique

Pure tin oxide thin films doped with cobalt in different concentrations were successfully synthesized using a Sol-Gel technique (Dip Coating). Excess cobalt atoms were added in the SnO2 network to compensate for the lack of oxygen and improve its properties Characterization techniques by XRD, SEM, EDX, FTIR, UV-vis, AFM, and l'effet hall were applied to characterize all the prepared films. XRD analysis revealed that all samples exhibited polycrystalline rutile-type tetragonal crystal structures, with crystal size decreasing from 14.90 nm to 8 nm as cobalt concentration increased, Using EDX analysis technique the elemental composition of SnO2 thin films mixed with cobalt was revealed, (FTIR) study showed that all the films exhibit the Sn-O, Sn-O-Sn, Sn-OH, and O-C-O vibration peaks. The Co doped SnO2 films enhanced the crystal structure and raised the optical energy gap from 3.85 eV to 4.1 eV, AFM images of photos of thin films doped with 6% Co have shown a significant improvement in surface roughness. Hall measurements showed that the conduction type shifted from n to p when the Increase in electrical resistance directly with increasing cobalt concentration to 9% by weight 79. 29 x 103 Omega.Cm to 7703 x 103 Omega.Cm.