skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structural Instability of Sn-Doped In2O3 Thin Films During Thermal Annealing at Low Temperature

Abstract

We report on observations of structural stability of Sn-doped In{sub 2}O{sub 3} (ITO) thin films during thermal annealing at low temperature. The ITO thin films were deposited by radio-frequency magnetron sputtering at room temperature. Transmission electron microscopy analysis revealed that the as-deposited ITO thin films are nanocrystalline. After thermal annealing in a He atmosphere at 250 C for 30 min, recrystallization, coalescence, and agglomeration of grains were observed. We further found that nanovoids formed in the annealed ITO thin films. The majority of the nanovoids are distributed along the locations of the original grain boundaries. These nanovoids divide the agglomerated larger grains into small coherent domains.

Authors:
; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
915661
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: Thin Solid Films; Journal Volume: 515; Journal Issue: 17, 2007
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; AGGLOMERATION; ANNEALING; COALESCENCE; GRAIN BOUNDARIES; INSTABILITY; MAGNETRONS; RECRYSTALLIZATION; SPUTTERING; STABILITY; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; Solar Energy - Photovoltaics

Citation Formats

Yan, Y., Zhou, J., Wu, X. Z., Moutinho, H. R., and Al-Jassim, M. M. Structural Instability of Sn-Doped In2O3 Thin Films During Thermal Annealing at Low Temperature. United States: N. p., 2007. Web. doi:10.1016/j.tsf.2007.01.040.
Yan, Y., Zhou, J., Wu, X. Z., Moutinho, H. R., & Al-Jassim, M. M. Structural Instability of Sn-Doped In2O3 Thin Films During Thermal Annealing at Low Temperature. United States. doi:10.1016/j.tsf.2007.01.040.
Yan, Y., Zhou, J., Wu, X. Z., Moutinho, H. R., and Al-Jassim, M. M. Mon . "Structural Instability of Sn-Doped In2O3 Thin Films During Thermal Annealing at Low Temperature". United States. doi:10.1016/j.tsf.2007.01.040.
@article{osti_915661,
title = {Structural Instability of Sn-Doped In2O3 Thin Films During Thermal Annealing at Low Temperature},
author = {Yan, Y. and Zhou, J. and Wu, X. Z. and Moutinho, H. R. and Al-Jassim, M. M.},
abstractNote = {We report on observations of structural stability of Sn-doped In{sub 2}O{sub 3} (ITO) thin films during thermal annealing at low temperature. The ITO thin films were deposited by radio-frequency magnetron sputtering at room temperature. Transmission electron microscopy analysis revealed that the as-deposited ITO thin films are nanocrystalline. After thermal annealing in a He atmosphere at 250 C for 30 min, recrystallization, coalescence, and agglomeration of grains were observed. We further found that nanovoids formed in the annealed ITO thin films. The majority of the nanovoids are distributed along the locations of the original grain boundaries. These nanovoids divide the agglomerated larger grains into small coherent domains.},
doi = {10.1016/j.tsf.2007.01.040},
journal = {Thin Solid Films},
number = 17, 2007,
volume = 515,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Silver doped cupric oxide thin films are prepared on polyethylene naphthalate (flexible polymer) substrates. Thin films Ag-doped CuO are deposited on the substrate by co-sputtering followed by microwave assisted oxidation of the metal films. The low temperature tolerance of the polymer substrates led to the search for innovative low temperature processing techniques. Cupric oxide is a p-type semiconductor with an indirect band gap and is used as selective absorption layer solar cells. X-ray diffraction identifies the CuO phases. Rutherford backscattering spectrometry measurements confirm the stoichiometry of each copper oxide formed. The surface morphology is determined by atomic force microscopy. Themore » microstructural properties such as crystallite size and the microstrain for (-111) and (111) planes are calculated and discussed. Incorporation of Ag led to the lowering of band gap in CuO. Consequently, it is determined that Ag addition has a strong effect on the structural, morphological, surface, and optical properties of CuO grown on flexible substrates by microwave annealing. Tauc's plot is used to determine the optical band gap of CuO and Ag doped CuO films. The values of the indirect and direct band gap for CuO are found to be 2.02 eV and 3.19 eV, respectively.« less
  • BaTiO{sub 3} thin films were grown on (001) SrTiO{sub 3} by reactive molecular beam epitaxy. Transmission electron microscopy studies showed that there is a high density of dislocation half-loops inside 8- and 12-nm-thick films. By thermal annealing at 1000 deg. C, the isolated small dislocation half-loops grow and combine to form a self-assembled regular dislocation network at the film/substrate interface. Threading dislocations in the films are removed and the lattice mismatch strain in the film is nearly completely relaxed by annealing at high temperature.
  • ZnO thin films were epitaxially grown on Al{sub 2}O{sub 3} (0001) substrates in a radio-frequency (rf) magnetron sputtering chamber. The surface morphology of ZnO was remarkably affected by the incorporation of a low-temperature grown ZnO buffer as well as the changes in rf-power. X-ray diffractions, combined with the surface micropits, revealed strain relaxations in the ZnO epilayers grown with higher rf-powers, which in turn caused a redshift to the intrinsic exciton absorption peak. Strain relaxations were also observed in the ZnO epilayers upon thermal annealing, which led to a redshift in the E{sub 2}{sup high} Raman mode. A factor ofmore » approx0.7 cm{sup -1} GPa{sup -1}, i.e., a biaxial stress of 1 GPa can shift the E{sub 2}{sup high} mode by 0.7 cm{sup -1}, was obtained. The point defects related absorptions and the exciton localizations were suppressed by annealing, which, in conjunction with the strain-relaxation induced redshift in the intrinsic-exciton absorptions, steepened the absorption edge and increased the optical bandgap energy of the ZnO epilayer.« less
  • Highlights: Black-Right-Pointing-Pointer We deposited nanocrystalline PbS thin films by chemical bath deposition technique. Black-Right-Pointing-Pointer We examined the effect of Sn doping and annealing on their structural and optical properties. Black-Right-Pointing-Pointer The crystallite size increases with increasing doping concentration in pure PbS. Black-Right-Pointing-Pointer The band gap of pure PbS was 1.8 eV which is higher than bulk PbS. Black-Right-Pointing-Pointer Band gap reduces with increasing doping concentration in pure PbS. -- Abstract: Nanocrystalline PbS and Sn doped PbS thin films were successfully deposited on suitably cleaned glass substrate at constant room temperature, using the chemical bath deposition technique. Before, adding Sn dopingmore » content, the pure PbS thin films were deposited at room temperature for several dipping times to optimize the deposition time. After deposition, the films were also annealed at 400 Degree-Sign C for 1 h in air. The crystal structures of the films were determined by X-ray diffraction studies. The films were adherent to the substrate and well crystallized according to cubic structure with the preferential orientation (2 0 0). The crystallite size of the pure PbS thin films at optimized deposition time 30 min was found to be 40.4 nm, which increased with Sn content in pure PbS thin film. The surface roughness was measured by AFM studies. The band gaps of the films were determined by transmission spectra. Experiments showed that the growth parameters, doping and annealing, influenced the crystal structure, and optical properties of the films.« 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