Low-Cost Inorganic Solar Cells: From Ink To Printed Device

Sn doping effects on the electro-optical properties of sol gel derived transparent ZnO films

Al-doped ZnO thin films grown onto ITO substrates as photoanode in dye sensitized solar cell

Transparent conducting properties of Ni doped zinc oxide thin films prepared by a facile spray pyrolysis technique using perfume atomizer

Al-doped zinc oxide (AZO) thin films are prepared on polycrystalline fluorine-doped tin oxide-coated conducting glass substrates from nitrates baths by the electrodeposition process at 70 °C. The electrochemical, morphological, structural and optical properties of the AZO thin films were investigated in terms of different Al concentration in the starting solution. It was found that the carrier density of AZO thin films varied between −3.11 and −5.56 × 1020 cm−3 when the Al concentration was between 0 and 5 at.%. Atomic force microscopy images reveal that the concentration of Al has a very significant influence on the surface morphology and roughness of thin AZO. X-ray diffraction spectra demonstrate preferential (002) crystallographic orientation having c-axis perpendicular to the surface of the substrate and average crystallites size of the films was about 33–54 nm. With increasing Al doping, AZO films have a strong improved crystalline quality. As compared to pure ZnO, Al-doped ZnO exhibited lower crystallinity and there is a shift in the (002) diffraction peak to higher angles. Due to the doping of Al of any concentration, the films were found to be showing >80 % transparency. As Al concentration increased the optical band gap was also found to be increase from 3.22 to 3.47 eV. The room-temperature photoluminescence spectra indicated that the introduction of Al can improve the intensity of ultraviolet (UV) emission, thus suggesting its greater prospects in UV optoelectronic devices. A detailed comparison and apprehension of electrochemical, optical and structural properties of ZnO and ZnO:Al thin films is done for the determination of optimum concentration of Al doping.

Effect of Al concentrations on the electrodeposition and properties of transparent Al-doped ZnO thin films

Aluminum doped zinc oxide (Al-doped ZnO) thin films were deposited by the spray pyrolysis technique onto the glass substrates at 450 °C using anhydrous zinc chloride (ZnCl 2 ) and aluminum chloride (AlCl 3 ) as sources of zinc and aluminum ions, respectively. The effect of [Al]/[Zn] ratio in the solution on the structural, optical, electrical and cathodoluminescence properties of these films were investigated. XRD study revealed that both undoped and Al-doped ZnO films were polycrystalline with hexagonal structure and exhibited (0 0 2) preferential orientation. The optical and electrical studies showed that the film deposited with the [Al]/[Zn] ratio equal to 0.05 had high transmittance (of about 80% and 95% in the visible and near infra-red regions, respectively) and minimum resistivity of 1.4×10 −3  Ω cm, respectively. This resistivity value decreased with increase in temperature indicating the semiconducting nature of Al-doped ZnO films. The chemical composition analysis (EPMA) showed that this film was nearly stochiometric with a slight oxygen deficiency.

M. Addou

Papers

The effect of Al-doping on the structural, optical, electrical and cathodoluminescence properties of ZnO thin films prepared by spray pyrolysis