The aim of the present study was to deposited and characterized Zn-doped SnO2 thin films for different weight concentrations (wt.%) 0, 3, 5 and 7% produced by spray pyrolysis. The characterization by XRD showed that the layers are polycrystalline in nature, with tetragonal structure of rutile type due to the presence of intense peak of orientation (110) located around the angle 26 ° for all the films produced. The variations in FWHM and the crystallite size were very well correlated. The SEM micrograph shows a relatively dense and smooth surface exhibited by the 3 wt.% doped film. This result can be explained by considering the following reasons: the substitution of the Sn+4 cations for the Zn+2 cations facilitate, the crystallite size increase and the decrease in defects. The contact angles measured using water droplets were less than 90 ° for all the films produced, which proves the hydrophilic characteristic of the films, meanwhile the film doped with 3 wt.% Zn had a high contact angle (88.09°). This result suggests that a doping concentration equal to 3 wt.% Zn can be considered as a critical concentration in changing the surface morphology of the Zn-doped SnO2 films produced. The analysis by UV-visible spectrophotometer showed a transmittance varying between 76 to 87% depending on the doping. The 3 wt.% Zn-doped SnO2 film was found to have high transmittance (87%) and better optical property with minimum resistivity (ρ = 0.044 Ω.cm) among the deposited films. This work demonstrated that the 3 wt.% Zn-doped SnO2 film improves the physical properties of the SnO2 film, allowing it to be integrated into the optoelectronic device.

This work reports on the development and characterization of Zinc Oxide (ZnO) nanocrystalline thin films deposited on glass substrates by spray pyrolysis method. The effect of 1 % Mg-doping and 6 % F/ x % Mg co-doping (x  1, 2 and 3) on the structural, morphological, optical and electrical properties of the films obtained is studied. The structural characterization shows that all the deposited layers are polycrystalline with a hexagonal wurtzite-type structure due to the existence of a more intense peak relative to the (002) peak, located around an angle of 34.13° with no other phase detected. The measured contact angles are more than 90° for pure, doped and 6 % F/1 % Mg co-doped films prepared, which confirms the hydrophobic character, while other co-doped films (6 % F:2 % Mg and 6 % F:3 % Mg) show the hydrophilic character at values of the contact angle  90°. A higher transmittance value of 86.47 %, a wide band gap of 3.53 eV and lower disorder (330.03 meV) are observed for the 6 % F:1 % Mg co-doped film. Co-doping with 1 % Mg considerably improves the electrical conductivity (  0.030 (Ω.cm) -1 ). The results suggest that the co-doped ZnO film (6 % F, 1 % Mg) can be used as a window film in thin film solar cells.

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Polycrystalline films of undoped and fluorine-doped SnO2 (FTO) are deposited on a glass substrate by spray pyrolysis at 400 °C. The effects of fluor concentration (8, 10 and 12 %) on the structural, morphological, optical and electrical properties of FTO films are studied. Our XRD results show that F-SnO2 still has the same rutile structure as undoped SnO2 with improved crystallization for doped films, with no other phase detected. The measured contact angles are  90° for undoped and 8 % F doped films, which confirms the hydrophilic character, while other doped (SnO2:10 % F and SnO2:12 % F) films show the hydrophobic character at contact angle values of  90° and the super-hydrophobic (CA = 140°) for SnO2:12 % F thin film. A higher transmittance value of 83 %, a wide band gap equal to 3.9 eV, and lower disorder (287.68 meV) are observed for the 12 % F doped SnO2 film. In addition, electrical resistivity (), carrier concentration (n) and Hall mobility () are determined from Hall effect measurements and it is found that all the elaborated thin films have n-type conductivity. The lowest resistivity of 2.245  10 -4 Ωcm and the highest Hall mobility of 24.55 cm 2 V -1 s -1 are obtained at an F concentration of 12 %. The results suggest that the FTO film at 12 %F can be used as a transparent conductive oxide of the front electrode for film solar cells.

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