Suchergebnisse

Ergebnisse 1 - 10 von 26 :

  • "ZnO thin film" x
Alle zurücksetzen
(0 0 2)-oriented growth and morphologies of ZnO thin films prepared by sol-gel method

1 Introduction Zinc oxide (ZnO) is an n-type semiconductor with a wide direct band gap of 3.37 eV and a large exciton binding energy (60 meV). ZnO thin films have been widely applied in high technology such as optoelectronic devices, solar cells, piezoelectric transducers and gas sensors [ 1 – 7 ]. Many techniques have been utilized to prepare ZnO thin films, such as metal organic chemical vapor deposition, pulsed laser deposition, sputtering, hydrothermal, sol-gel method, etc. [ 8 – 18 ]. Due to the low cost and simple equipment, sol-gel method has been

Open access
Optical Properties of ZnO Thin Film

Abstract

In this work, we studied with a Matlab program, some of optical properties of zinc oxide (ZnO) deposited on glass (SiO2). The parameters studied include the refraction index, extinction coefficient, optical band gap, and complex dielectric constant versus incident photon energy, and transmittance, absorbance and reflectance spectrum of ZnO thin film deposited on glass (SiO2) for different thickness. The films were found to exhibit high transmittance (75- 95%), low absorbance and low reflectance in the visible / near infrared region up to 1000 nm. However, the absorbance of the films was found to be high in the ultra violet region with peak around 380 nm.

Open access
Effects of Al doping on defect behaviors of ZnO thin film as a photocatalyst

Abstract

Al doped ZnO (AZO) thin films were prepared on silica substrates by sol-gel method. The films showed a hexagonal wurtzite structure with a preferred orientation along c-axis. Suitable Al doping dramatically improved the crystal quality compared to the undoped ZnO films. Dependent on the Al dopant concentration, the diffraction peak of (0 0 2) plane in XRD spectra showed at first right-shifting and then left-shifting, which was attributed to the change in defect concentration induced by the Al dopant. Photocatalytic properties of the AZO film were characterized by degradation of methyl orange (MO) under simulated solar light. The transmittance of the films was enhanced by the Al doping, and the maximum transmittance of 80 % in the visible region was observed in the sample with Al concentration of 1.5 at.% (mole fraction). The film with 1.5 at.% Al doping achieved also maximum photocatalytic activity of 68.6 % under solar light. The changes in the film parameters can be attributed to the variation in defect concentration induced by different Al doping content.

Open access
Optical properties of the plasma hydrogenated ZnO thin films

electronic properties of H-doped ZnO”, Optical and Quantum Electronics , vol. 48 no. 5 (2016),. [4] P. Kelly and R. Arnell, “Magnetron sputtering: a review of recent developments and applications”, Vacuum , vol. 56 no. 3 (2000), 159-172. [5] Z. Remes, J. Stuchlik, A. Purkrt, Y.-Y. Chang, J. Jirasek, P. Stenclova, V. Prajzler and P. Nekvindova, “ZnO Thin Films Prepared by Reactive Magnetron Sputtering”, NANOCON 2016 - 8th International Conference on Nanomaterials - Research and Application , Conference Proceedings, 8 vol. Hotel Voronez I, Brno, Czech Republic

Open access
Structural and optical characterization of Cu doped ZnO thin films deposited by RF magnetron sputtering

References [1] S. Ilican, Y. Caglar, M. Caglar and B. Demirci, “Polycrystalline indium-doped ZnO thin films: preparation and characterization”, Journal of optoelectronics and advanced materials , vol. 10, pp. 2592–2598, 2008. [2] M. Suchea, S. Christoulakis, K. Moschovis, N. Katsarakis and G. Kiriakidis, “ZnO transparent thin films for gas sensor applications”, Thin Solid Films , vol. 515, pp. 551–554, 2006. [3] J. Huang, Z. Yin and Q. Zheng, “Applications of ZnO in organic and hybrid solar cells”, Energy&Environmental Science , vol. 4, pp

Open access
Production of ZnO and CdO-ZnO thin Films by Extraction–Pyrolytic Method

deposited by the sol-gel method. Thin Solid Films . 426 , 94–99. 11. Hiramatsu, M., Imaeda, K., Horio, N., and Nawata, M. (1998). Transparent conducting ZnO thin films prepared by XeCl excimer laser ablation. J. Vac. Sci. Technol. A . 16 , 669–673. 12. Lee, J., Li, Z., Hodgson, M., Metson, J., Asadov, A., and Gao, W. (2004). Structural, electrical and transparent properties of ZnO thin films prepared by magnetron sputtering. Curr. Appl. Phys. 4 (2-4), 398–401. 13. Konstantinidis, S., Hemberg, A., Dauchot, J.P., and Hecq, M. (2007). Deposition of

Open access
Optical investigations of microwave induced synthesis of zinc oxide thin-film

Abstract

In this article, ZnO thin-film deposition on a glass substrate was done using microwave induced oxygen plasma based CVD system. The prepared thin-films were tested in terms of crystallinity and optical properties by varying the microwave power. The effect of power variation on the morphology and size of final products was carefully investigated. The crystal structure, chemical composition and morphology of the final products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, Raman spectroscopy and photoluminescence (PL). This technique confirmed the presence of hexagonal ZnO nanocrystals in all the thin-films. The minimum crystallite grain size as obtained from the XRD measurements was ~9.7 nm and the average diameter was ~18 nm.

Open access
Effect of substrate temperature on structural and optical properties of spray deposited ZnO thin films

Abstract

Undoped ZnO thin films have been prepared on glass substrates at different substrate temperatures by spray pyrolysis method. The effect of temperature on the structural, morphological and optical properties of n-type ZnO films was studied. The X-ray diffraction (XRD) results confirmed that the ZnO thin films were polycrystalline with wurtzite structure. Scanning electron microscopy (SEM) measurements showed that the surface morphology of the films changed with temperature. The studies demonstrated that the ZnO film had a transmission of about 85 % and energy gap of 3.28 eV at 450 °C. The RBS measurements revealed that ZnO layers with a thickness up to 200 nm had a good stoichiometry.

Open access
Rapid Annealing of Black ZnO Thin Films Prepared by Pulsed Laser Deposition

Rapid Annealing of Black ZnO Thin Films Prepared by Pulsed Laser Deposition

ZnO thin films were deposited by pulsed laser deposition (fluence 2.2 J/cm2) in vacuum on different substrates kept at room temperature. This temperature allowed for fast film growing, however the as-prepared films had low transparency. To improve this optical property, keeping up at the same time the high electric conductivity of the films, post-annealing procedures in vacuum and in air were carried out. The influence of these procedures on the optical absorption, photoluminescence and electrical properties has been investigated. It is shown that the annealing in air improves only the transparency of such a film, however its conductivity decreases markedly. In turn, vacuum annealing for 3 min. at 600° C results in better transparency of the films, with their electric conductivity kept high.

Open access
Preparation and spectroscopic analysis of zinc oxide nanorod thin films of different thicknesses

Abstract

Zinc oxide thin films with different thicknesses were prepared on microscopic glass slides by sol-gel spin coating method, then hydrothermal process was applied to produce zinc oxide nanorod arrays. The nanorod thin films were characterized by various spectroscopic methods of analysis. From the images of field emission scanning electron microscope (FESEM), it was observed that for the film thickness up to 200 nm the formed nanorods with wurtzite hexagonal structure were uniformly distributed over the entire surface substrate. From X-ray diffraction analysis it was revealed that the thin films had good polycrystalline nature with highly preferred c-axis orientation along (0 0 2) plane. The optical characterization done by UV-Vis spectrometer showed that all the films had high transparency of 83 % to 96 % in the visible region and sharp cut off at ultraviolet region of electromagnetic spectrum. The band gap of the films decreased as their thickness increased. Energy dispersive X-ray spectroscopy (EDS) showed the presence of zinc and oxygen elements in the films and Fourier transform infrared spectroscopy (FT-IR) revealed the chemical composition of ZnO in the film.

Open access