Papers by Keyword: Transparent Conducting Oxide

Abstract: Transparent conducting oxides (TCOs) are widely used as a transparent electrode in various fields of opto-and semiconductor electronics. The main materials used today are indium-tin oxide, tin-antimony oxide and zinc-aluminum oxide. The authors have developed and improved the spray-pyrolysis method, which is one of the most promising methods of implementation in production. In this work, the study of tin dioxide doped with antimony coatings and the development of a methodology for the controlled synthesis of TCO, taking into account the effect of technological modes of deposition on the TCO parameters. The results of the performed studies contribute to the development of an automated technology for the synthesis of transparent conducting oxides with desired properties.

Abstract: Aluminium (Al) doped zinc oxide (ZnO) has been considered as one of the promising transparent conducting oxide for wide applications in electronic devices. In this investigation, sol-gel spin coating process were employed to fabricate Al:ZnO on glass coated with indium tin oxide (ITO) substrate. In order to expose the effects of aluminium concentration on the structural and electrical properties of the ZnO films, different Al concentrations (1 at.%, 3 at.% and 5 at.%) were used. A field emission scanning electron microscope (FESEM) and a two point probe were employed to examined the material properties of the Al:ZnO films. Through the FESEM results, the Al:ZnO films show different morphologies behaviour with increasing the Al concentrations. Besides, the electrical conductivity was increased by increasing the dopant source and the lowest resistivity was obtained at 5 at.%. In general, the Al concentration exerts strong influence on the ZnO films properties. Keywords: Transparent conducting oxide, X-ray diffraction, sol gel

Abstract: In this paper, AZO thin films of different thicknesses were deposited on glass substrates as transparent conducting (TCO) films by changing the deposition time using a DC magnetron sputtering method. The effect of film thicknesses on the structural and optical properties of AZO films was investigated using X-ray diffractometer (XRD) and spectrophotometer, respectively. Results show that increasing the film thickness results in decreasing the optical transmittance. The optimum properties were obtained for a film with 500 nm thickness and 90 min deposition time, which exhibited a transmittance of 95%.

Abstract: The structure, elastic and electronic properties of 2H-CuGaO₂ are calculated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory. The calculated equilibrium lattice parameters is in good agreement with experimental and reported values. The elastic coefficients, bulk, shear and Youngs modulus, Poissons ratio and elastic anisotropy ratio of 2H-CuGaO₂ were calculated. The electronic properties of 2H-CuGaO₂ have been calculated and the results show that 2H-CuGaO₂ has an indirect band gap.

Abstract: Transparent conducting aluminum-doped zinc oxide (AZO) films with different film thickness had been prepared on soda-lime glass substrates by radio frequency magnetron sputtering using a high density ceramic target. The structural, morphology, electrical, and optical properties of the AZO thin films were investigated by X-ray diffraction, scanning electron microscope, Hall-effect measurement and optical transmission spectroscopy, which were strongly influenced by film thickness. With the film thickness increasing from 140 nm to 710 nm, the resistivity decreases from 9.78 × 10³ to 3.23 × 10³ Ω.cm and an average optical transmission decreases from 88% to 80% in the visible range and the optical bandgap decreases from 3.47 to 3.24 eV.

Abstract: The ultrahigh density Gallium (Ga2O3 1 wt%) doped zinc oxide (ZnO, 99wt%) targets were prepared by air sintering. The relative density, conductivity, bending strength, Vickers hardness and shrinkage ratio of GZO targets were measured. The morphologies and microstructures were characterized by XRD and SEM. It turns out that sintered GZO targets achieved a relative density of 98%, square resistance of 7Ω/□, Vickers hardness of 310HV and a bending strength of 90.79MPa. The best sintering temperature is 1300°C. The Ga2O3 added can effectively enter into the ZnO lattice structure to form solid solution during sintering. The second phase of GaZn2O4 turned out when the sintering temperature was 1350°C.

Abstract: Polycrystalline Al-doped ZnO (AZO) thin films with a thickness of 1300 Å were grown on Corning 1737 glass by pulsed laser deposition (PLD) at a low substrate temperature. The presence of oxygen gas during deposition led to a remarkable enhancement of the (002) c-axis preferential orientation as well as increased crystallite size. Highly transparent films with a transmittance of 85% could be obtained by controlling the oxygen flow rate, while causing a Burstein-Moss shift toward a shorter wavelength as well. The resistivities of the films were found to be functions of both the oxygen flow rate and substrate temperature, with the lowest value being 2.3 x 10-4 Ωcm (18Ω/sq sheet resistance). It was found that both the oxygen flow rate and substrate temperature are crucial in order to grow superior device quality films with an appropriate degree of crystallinity, less surface roughness, high transmittance and low resistivity, which are characteristics of great technological importance.

Abstract: CuAlO₂ is an important p-type transparent conductive oxide (TCO) material. Thus, in this paper, the structure and properties of 2H-CuAlO₂ are calculated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory. The calculated equilibrium lattice parameters is in good agreement with experimental and reported values. The energy band gap of 2H-CuAlO₂ has been calculated and the results shows that 2H-CuAlO₂ has an indirect band gap. The density of state for 2H-CuAlO₂ has also been calculated.

Abstract: This work reports the synthesis of novel quaternary transparent conducting oxide Cd_(1-x)Sn_(1-x)In_xGa_xO₃( x=0.1, 0.2, 0.3) at 1225°C via solid state reaction route. The investigations on structural, optical and electrical properties have been carried out. Powder X-ray diffraction revealed the phase purity and distorted orthorhombic structure of the species synthesized. Distortion of the structure is due to the substitution of In³⁺ and Ga³⁺ in CdSnO3 (JCPDS card no.340885) matrix. The optical transmittance approximated by the reflectance shows considerable increase in the transmittance of visible light along with the increase of substitution. Typical Burstein-Moss effect is observed with the increase in x value as a variation in optical bandgap from 2.7 to 2.9eV. Four point Hall measurements by Van der-Pauw method exhibit superior properties in charge carrier concentration and mobility. Maximum bulk charge concentration of 4.78x1017 cm^-3 is obtained for x=0.3. Hall mobility depends on carrier concentration and steeply increases with the carrier concentration. Considerable drop in the resistivity of the material along with higher transmittance is a critical finding in the experiment.

Abstract: Low resistivity, fluorine-doped tin dioxide thin films were deposited on glass substrates by spray pyrolysis. These films were prepared with different F-doping concentrations from 0 to 33 mol%. The structure of these films was investigated by X-ray diffraction and the surface morphology by Scanning Electron Microscopy. Sample compositions were evaluated using X-ray Photoemission Spectroscopy. According to these results, the films were all polycrystalline with tetragonal crystal structures. Hall measurements were used to probe the dependence of the resistivity on temperature for un-doped SnO₂ and F-doped SnO₂. The resistivity of un-doped SnO2 slightly increased with increasing temperature. Conversely, the resistivity of F-doped SnO₂ slightly decreased with increasing temperature.