No abstract

No abstract

Structural and magnetic properties of Zn[Formula: see text]NixO thin films and diluted magnetic semiconductors have been investigated. This sample has been synthesized using a spray pyrolysis technique with a stoechiometric mixture of zinc acetate (C4H6O4Zn[Formula: see text]2H2O) and Nickel acetate (C4H6O4Ni[Formula: see text] 2H2O) on a heated glass substrate at 450[Formula: see text]C. The films were characterized by X-ray diffraction (XRD), UV–Vis spectrophotometry and Hall Effect measurements. These films of ZnO crystallized in the hexagonal Wurtzite structure. The optical study showed that the band-gap energy was increased, from 3.3[Formula: see text]eV to 3.5[Formula: see text]eV, with increasing the Ni concentration. The film resistivity was affected by Ni-doping, and the best resistivity value 1.15[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text] ([Formula: see text] cm) was obtained for the film doped with 2 at.% Ni. The electronic structure and optical properties of the Wurtzite structure Zn[Formula: see text]NixO were obtained by first-principles calculations using the Korringa–Kohn–Rostoker method combined with the coherent potential approximation (CPA), as well as CPA confirm our results.

In doped ZnO (IZO), In-Al co-doped ZnO (IAZO) and In-F co-doped ZnO (IFZO) were deposited on glass substrates at 350 °C by spray pyrolysis technique. The structural, optical and electrical properties of as-deposited thin films were investigated and compared. A polycrystalline and (002) oriented wurtzite crystal structure was confirmed by X-ray patterns for all films; and the full width at half-maximum (FWHM) of (002) diffraction peak increased after co-doping. The investigation of the optical properties was performed using Uv-vis spectroscopy. The average transmittances of all the films were between 70 and 85%. Hall Effect measurements showed that the electrical conductivity of co-doped films increased as compared with IZO thin film. The highest conductivity of about 16.39 Ω-1 cm-1 was obtained for as-deposited IFZO thin film. In addition, the thin films were annealed at 350 °C for two hour under Ar atmosphere and their optical, electrical properties and the associated photoluminescence (PL) responses of selected films were analysed. After annealing, the electrical conductivity of all thin films was improved and the optical transmittance remained above 70%. Room temperature PL revealed that the annealed IAZO thin film had a strong green emission than that of IZO film.

Structural, optical and electrical properties of (ytterbium/terbium) co-doped ZnO thin films deposited on glass substrates using the spray pyrolysis method were investigated. The films exhibited the hexagonal wurtzite structure with a preferential orientation along (002) direction. No secondary phase was observed in the X-ray diffraction detection limit. Atomic force microscopy (AFM) was performed and root means square roughness (RMS) of our samples decreased with terbium content. Photoluminescence measurements showed a luminescence band at 980 nm which is characteristic of Yb3+ transition between the electronic levels 2F5/2 to 2F7/2. This is experimental evidence for an efficient energy transfer from the ZnO matrix to Yb. Hall Effect measurements gave a low electrical resistivity value around 6.0 × 10−3 Ω.cm. Such characteristics make these films of interest to photovoltaic devices.