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Title: The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation

Abstract

Tin doped indium oxide (ITO) thin films with composition of 9.42 wt% SnO{sub 2} and 89.75 wt% In{sub 2}O{sub 3,} and impurities balanced on glass substrates at room temperature have been prepared by electron beam evaporation technique and then were annealed in air at different temperatures from 350 to 550 deg. C for 1 h. XRD pattern showed that increasing annealing temperature increased the crystallinity of thin films and at 550 deg. C high quality crystalline thin films with grain size of about 37 nm were obtained. Conductivity of ITO thin films was increased by increasing annealing temperature and conductivity obtained results in 350-550 deg. C temperature range were also excellently fitted in both Arrhenius-type and Davis-Mott variable-range hopping conductivity models. The UV-vis transmittance spectra were also confirmed that the annealing temperature has significant effect on the transparency of thin films. The highest transparency over the visible wavelength region of spectrum (93%) obtained at 550 deg. C on annealing temperature. It should be noted that this thin film was deposited on substrate at room temperature. This result obtained is equivalent with those values that have already been reported but with high-level (20 wt%) tin doped indium oxide thin films andmore » also at 350 deg. C substrate temperature. The allowed direct band gap at the temperature range 350-550 deg. C was estimated to be in the range 3.85-3.97 eV. Band gap widening with an increase in annealing temperature was observed and is explained on the basis of Burstein-Moss shift. A comparison between the electron beam evaporation and other deposition techniques showed that the better figure of merit value can be obtained by the former technique. At the end we have compared our results with other techniques.« less

Authors:
 [1];  [2];  [3];  [4]
  1. Quantum Optics Research Group, Department of Physics, University of Isfahan, Isfahan (Iran, Islamic Republic of). E-mail: hfallah@sci.ui.ac.ir
  2. Quantum Optics Research Group, Department of Physics, University of Isfahan, Isfahan (Iran, Islamic Republic of)
  3. Department of Chemistry, University of Urmia, Urmia (Iran, Islamic Republic of)
  4. Isfahan Optics Industry, Isfahan (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
21000605
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 42; Journal Issue: 3; Other Information: DOI: 10.1016/j.materresbull.2006.06.024; PII: S0025-5408(06)00273-X; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; DOPED MATERIALS; ELECTRON BEAMS; EVAPORATION; GLASS; GRAIN SIZE; IMPURITIES; INDIUM OXIDES; NANOSTRUCTURES; OPACITY; SUBSTRATES; THIN FILMS; TIN; TIN OXIDES; X-RAY DIFFRACTION

Citation Formats

Fallah, Hamid Reza, Ghasemi, Mohsen, Hassanzadeh, Ali, and Steki, Hadi. The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation. United States: N. p., 2007. Web. doi:10.1016/j.materresbull.2006.06.024.
Fallah, Hamid Reza, Ghasemi, Mohsen, Hassanzadeh, Ali, & Steki, Hadi. The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation. United States. doi:10.1016/j.materresbull.2006.06.024.
Fallah, Hamid Reza, Ghasemi, Mohsen, Hassanzadeh, Ali, and Steki, Hadi. Thu . "The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation". United States. doi:10.1016/j.materresbull.2006.06.024.
@article{osti_21000605,
title = {The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation},
author = {Fallah, Hamid Reza and Ghasemi, Mohsen and Hassanzadeh, Ali and Steki, Hadi},
abstractNote = {Tin doped indium oxide (ITO) thin films with composition of 9.42 wt% SnO{sub 2} and 89.75 wt% In{sub 2}O{sub 3,} and impurities balanced on glass substrates at room temperature have been prepared by electron beam evaporation technique and then were annealed in air at different temperatures from 350 to 550 deg. C for 1 h. XRD pattern showed that increasing annealing temperature increased the crystallinity of thin films and at 550 deg. C high quality crystalline thin films with grain size of about 37 nm were obtained. Conductivity of ITO thin films was increased by increasing annealing temperature and conductivity obtained results in 350-550 deg. C temperature range were also excellently fitted in both Arrhenius-type and Davis-Mott variable-range hopping conductivity models. The UV-vis transmittance spectra were also confirmed that the annealing temperature has significant effect on the transparency of thin films. The highest transparency over the visible wavelength region of spectrum (93%) obtained at 550 deg. C on annealing temperature. It should be noted that this thin film was deposited on substrate at room temperature. This result obtained is equivalent with those values that have already been reported but with high-level (20 wt%) tin doped indium oxide thin films and also at 350 deg. C substrate temperature. The allowed direct band gap at the temperature range 350-550 deg. C was estimated to be in the range 3.85-3.97 eV. Band gap widening with an increase in annealing temperature was observed and is explained on the basis of Burstein-Moss shift. A comparison between the electron beam evaporation and other deposition techniques showed that the better figure of merit value can be obtained by the former technique. At the end we have compared our results with other techniques.},
doi = {10.1016/j.materresbull.2006.06.024},
journal = {Materials Research Bulletin},
number = 3,
volume = 42,
place = {United States},
year = {Thu Mar 22 00:00:00 EDT 2007},
month = {Thu Mar 22 00:00:00 EDT 2007}
}
  • High quality gallium doped zinc oxide (GZO) films are prepared by electron beam evaporation technique. The effect of substrate temperature on structural, electrical and optical properties was studied in detail. The prepared films are polycrystalline in nature with c-axis perpendicular to the substrate. The resistivity of the film decreases and the optical transparency increases as the substrate temperature increases from room temperature to 150 deg. C. The film produce the optical band gap of 3.47 eV.
  • PLZT films prepared by a sol-gel process were fabricated on indium tin oxide (ITO)-coated glass substrates using rapid thermal annealing (RTA). The films crystallized into the perovskite phase when annealed at 750 C for 5 min. X-ray diffraction (XRD) and Raman spectroscopy results indicate that the morphotropic phase boundary of PLZT films shifts toward the Ti-rich side, in contrast to that of bulk ceramics. A dielectric constant of 1,270 for the 2/55/45 composition was the maximum value observed. With increasing Zr content in the 2 mol% La modified films, the coercive field decreased from 52.9 to 30 kV/cm and themore » remanent polarization increased from 22.7 to 50.6 {micro}C/cm{sup 2}. Optical transmittance increased by increasing optical isotropy as the Zr content increased.« less
  • Highlights: • ITO nanowires were grown by e-beam evaporation method. • ITO nanowires growth done at low substrate temperature of 350 °C. • Nanowires growth was carried out without use of catalyst and reactive oxygen gas. • Nanowires growth proceeds via self catalytic VLS growth. • Grown nanowires have diameter 10–20 nm and length 1–4 μm long. • ITO nanowire films have shown good antireflection property. - Abstract: We report the self catalytic growth of Sn-doped indium oxide (ITO) nanowires (NWs) over a large area glass and silicon substrates by electron beam evaporation method at low substrate temperatures of 250–400more » °C. The ITO NWs growth was carried out without using an additional reactive oxygen gas and a metal catalyst particle. Ultrafine diameter (∼10–15 nm) and micron long ITO NWs growth was observed in a temperature window of 300–400 °C. Transmission electron microscope studies confirmed single crystalline nature of the NWs and energy dispersive spectroscopy studies on the NWs confirmed that the NWs growth proceeds via self catalytic vapor-liquid-solid (VLS) growth mechanism. ITO nanowire films grown on glass substrates at a substrate temperature of 300–400 °C have shown ∼2–6% reflection and ∼70–85% transmission in the visible region. Effect of deposition parameters was systematically investigated. The large area growth of ITO nanowire films would find potential applications in the optoelectronic devices.« less
  • Zn{sub 1-x}Cd{sub x}O thin films have been prepared by sol-gel spin coating method. Structural analysis shows that the Cd substitution into the wutrzite ZnO lattice is achieved up to about 20 mol %. The optical band gap is found to decrease with the increase in Cd content. Increase in the annealing temperature up to a certain critical temperature leads to band gap narrowing because of the proper substitution of Zn by Cd and thereafter the band gap increases due to Cd re-evaporation from the lattice sites. This critical temperature lowers down with the increase in Cd doping concentration. The resistivity decreasesmore » with the increase in Cd content and increases with the increase in annealing temperature.« less
  • Highlights: • Nanostructured hematite thin films were synthesized via electrodeposition method. • Effects of annealing on size, grain boundary and PEC properties were examined. • Photocurrents generation was enhanced when the thin films were annealed at 600 °C. • The highest photocurrent density of 1.6 mA/cm{sup 2} at 0.6 V vs Ag/AgCl was achieved. - Abstract: Hematite (α-Fe{sub 2}O{sub 3}) is a promising photoanode material for hydrogen production from photoelectrochemical (PEC) water splitting due to its wide abundance, narrow band-gap energy, efficient light absorption and high chemical stability under aqueous environment. The key challenge to the wider utilisation of nanostructuredmore » hematite-based photoanode in PEC water splitting, however, is limited by its low photo-assisted water oxidation caused by large overpotential in the nominal range of 0.5–0.6 V. The main aim of this study was to enhance the performance of hematite for photo-assisted water oxidation by optimising the annealing temperature used during the synthesis of nanostructured hematite thin films on fluorine-doped tin oxide (FTO)-based photoanodes prepared via the cathodic electrodeposition method. The resultant nanostructured hematite thin films were characterised using field emission-scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV-visible spectroscopy and Fourier transform infrared spectroscopy (FTIR) for their elemental composition, average nanocrystallites size and morphology; phase and crystallinity; UV-absorptivity and band gap energy; and the functional groups, respectively. Results showed that the nanostructured hematite thin films possess good ordered nanocrystallites array and high crystallinity after annealing treatment at 400–600 °C. FE-SEM images illustrated an increase in the average hematite nanocrystallites size from 65 nm to 95 nm when the annealing temperature was varied from 400 °C to 600 °C. As the crystallites size increases, the grain boundaries reduce and this suppresses the recombination rate of electron–hole pairs on the nanostructured hematite thin films. As a result, the measured photocurrent densities of nanostructured hematite thin films also increased. The highest measured photocurrent density of 1.6 mA/cm{sup 2} at 0.6 V vs Ag/AgCl in 1 M NaOH electrolyte was achieved for the nanostructured hematite thin film annealed at 600 °C. This study had confirmed that strong interdependencies exist between the average hematite nanocrystallites size and grain boundaries with annealing temperature on the eventual PEC water splitting performance of nanostructured hematite thin films. The annealed hematite thin films at a higher temperature will enhance the nanocrystals growth and thus, suppressing the electron–hole pairs recombination rate, lowering the grain boundary resistance and enabling higher photocurrent flow at the molecular level. As a result, the photocurrent density and thus, the overall PEC water splitting performance of the nanostructured hematite thin films are significantly enhanced.« less