Effect of solution flow rate on growth and characterization of nanostructured ZnO thin films deposited using spray pyrolysis

ZnO thin films were grown from 60 ml of spray solution on glass substrates by chemical spray at 300°C using solution low spray rates of 5, 10, 15 and 20 ml/h. X-ray diffraction data showed films grow preferentially in the (100) plane parallel to the substrate, with average grain size ranged from 20.6 nm to 35.3 nm. The electrical resistivity of sprayed ZnO thin films is controlled by the solution spray rate, it decreases from 4.048×10 3 Ω cm to 0.781×10 3 Ω cm respectively when spray rate is increased from 5ml/h to 20 ml/h independent of the film thickness; Sprayed ZnO films transmit 9799 % of the visible light. The optical band gap energy is found to be direct allowed transition ~3.26 eV. At optimal solution spray rate Sf = 15 ml/h, the ZnO thin film exhibits low sheet resistance Rs = 5.25×10 9 Ω/□ and highest figure of merit ΦTC = 17.4×10 -11 Ω -1 .