Synthesis and Characterization of Sn-Doped CuO Thin Films for Gas Sensor Toward H2S Gas Sensing

In this work, thin films of CuO doped with 3% SnCl2 (0.97 g CuO-0.03 g SnCl2) were deposited on glass substrates using a sol-gel spin coating technique. The deposited thin films were annealed in a muffle furnace at 400 degrees C for 2 h. UV-visible spectroscopy, a two-probe setup, and x-ray diffraction were utilized to analyze the optical, electrical, and structural properties, respectively. The optical bandgap of the doped films was identified within the range of 3.7-3.83 eV. Electrical investigation performed by the two-probe setup revealed that the prepared samples were ohmic in nature. It was found that the resistivity of the samples varied from 11.86 Omega<middle dot>m to 6.04 Omega<middle dot>m as the thickness of films increased from 165 nm to 570 nm. The gas-sensing properties of the prepared films were assessed at different operational temperatures and for varying concentrations of hydrogen sulfide gas. From the obtained data, it was observed that SnCl2-doped CuO thin films show excellent response toward H2S gas at room temperature.