^aDepartment of Physics, College of Education, University of Masan, Iraq

^bDepartment of Physics, College of Scienc, Mustansiriyah University, Iraq

c Department of Physics, College of Education, University of Garmian, Iraq

^dDepartment of Radiology, Al-Manara College for Medical Science, Iraq

^eDepartment of Radiation and Sonar Technologies, Alnukhba, University College, Iraq

On glass substrates, silver (Ag) doped Titanium dioxide (TiO2) films at varied levels of concentrations (0, 2, and 4) % wt were synthesized by chemical spray pyrolysis (CSP). As per the X-ray diffraction pattern, the only phases present in the sample were anatase and rutile TiO2. Using AFM, it was discovered that the TiO2 thin films were smooth and compact; however, the surface roughness increases as the dopant amount decreases. SEM images display TiO2 films. Surface transformation is evident with uniform spherical nano- grains after Ag doping. The optical characteristics of wavelength range (300-900) nm have been investigated using absorbance and transmittance spectra. The results revealed that the films have a 65-75 % transmittance in VIS-NIR spectra for all films. The allowable direct electronic transitions have (3.15-3.25) eV energy gaps. At 250 ppm, the NH3 gas sensor exhibited increased resistance, indicating heightened sensitivity. Sensitivity decreases with concentration increases to 0 %, 2 %, and 4 % of Ag for NH3 gas. Reduction observed:

18.4% to 4.6% (50 ppm), 20.7% to 6.8% (150 ppm), and 25.9% to 8.2% (250 ppm).