Doped ZnO Thin Films Properties/Spray Pyrolysis Technique
Résumé
In this contribution, the effect of different dopants (Al, Sn, and Cu) on the structure, texture and optical properties of ZnO thin films was investigated. Al-doped ZnO (AZO), Sn-doped ZnO (TZO) and Cu-doped ZnO (CZO) thin films are synthesized by chemical spray pyrolysis technique on glass substrates. The so-obtained films crystallized in hexagonal wurtzite polycrystalline structure. The pole figures show that all the thin films have (0002) as the preferred orientation along the c-axis with the highest level was obtained in TZO thin film. The morphology film was significantly affected by the doping type. The transmittance spectra of all the films point out highly transparent in the visible range with an average transmittance higher than 80% for TZO and AZO films but with an average transmittance equal to about 70% for CZO film. Furthermore, the optical bandgap values were determined by the Tauc's law and were found to be 3.30 eV, 3.28 eV and 3.27 eV for AZO, TZO, and CZO thin films, respectively. The Urbach energy of the films was also calculated.