The synthesis and characterization of sprayed ZnO thin films: As a function of solution molarity

In the present paper, the structural, electrical and optical properties of zinc oxide thin films were studied as a function of solution molarity. The ZnO thin films were deposited on glass substrates via the ultrasonic spray technique at 350 ◦ C. Polycrystalline films with a hexagonal wurtzite structure with (100) and (002) preferential orientation corresponding to ZnO films were observed. The optimal values of the crystallite size of the ZnO films were observed with (002) plan in 0.4 and 0.5 mol/l of solution molarity. All films exhibit an average optical transparency about 85%, in the visible region. The shift of optical transmittance towards smaller wavelength can be showed by the decrease of band gap caused by the change of crystallite size in polycrystalline. The maximum electrical conductivity of ZnO films was found of 2.29 (� .cm) -1 with 0.075 mol/l of solution molarity.