In this thesis, solar energy was used to prepare thin films by heating substrate. ZnO, NiO and SnO2 thin films were elaborated by spray pyrolysis technique and solar heat. ZnO samples were prepared at various substrate temperature, deposition rate and dopant ratio, whereas NiO and SnO2 layers were fabricated with different precursor concentration and deposition rate, respectively. The structural, optical and electrical proprieties were studied for all samples.
As results for ZnO thin films at different substrate temperature, the XRD patterns showed that the structural of all films is polycrystalline, the crystallite size increased greatly from 9.96 to 15.19 nm by increasing of deposition temperature from 350 to 450 ʻC. The transmission of films prepared at 350? exceeded 90%. For the effect of deposition rate, the obtained ZnO thin films are polycrystalline, an increase in the XRD intensity of the peaks has been noted. An average transmission of about 85% in the visible region was observed; whereas the estimated band gap energy decreased from 3.30 to 3.28eV. The resistivity decreased from 1.19 to 0.01(? cm). Regarding the effect of dopant, ZnO was doped by nickel (0, 1, 2, 3, and 6 at %), polycrystalline Ni-doped ZnO thin films were indicated. However, ?-Ni(OH)2 and ?-Ni(OH)2 were observed at 6 and 3 at % Ni, respectively. All thin films have a high optical transmission in the visible region of about 85%. The optical band gap energy increased from 3.26 eV for 0% to 3.34 eV for 1 at %, and further decreased to 3.27 eV for 6 at % Ni. The thin film deposited with 3 at % Ni has the lowest value of Urbach energy of 0.091eV. The electrical conductivity of the Ni-doped ZnO films increased greatly from 0.016 (? cm)-1 for 0% Ni to 0.042 (? cm)-1 for 3 at % Ni.
For NiO result of thin films prepared at different concentration (0.05, 0.10 and 0.15 mol.l-1). Polycrystalline NiO films with a cubic structure were observed at all sprayed films having as minimum crystallite size of 11.97nm was attained at 0.1 mol.l-1 concentration. However, ?-Ni (OH)2 was observed at 0.15 mol.l-1. The band gap energy varied from 3.54 to 3.76eV with low transmittance. The electrical conductivity of NiO film deposited at 0.15 mol.l-1 was 0.169 (?.cm)-1.
For SnO2, the characterization results of elaborated thin films at different deposition rates (5, 10 and 15ml) showed a polycrystalline structure with maximum crystallite size 35.3 nm for 10ml. The transmittance of prepared samples was about 60 % and the optical band gap energy increased from 3.2 eV for 5ml to 3.6 eV for 15ml. The electrical conductivity was increased from 0.01 (?.cm)-1 to 0.06 (?.cm)-1.