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Title: The role of copper in ZnO/Cu/ZnO thin films for flexible electronics

Abstract

ZnO/Cu/ZnO multilayer structures with very high conductivity have been obtained by magnetron sputtering. The Hall resistivity of the films was as low as 6.9x10{sup -5} OMEGA-cm with a carrier concentration of 1.2x10{sup 22} cm{sup -3} at the optimum copper layer thickness. The conduction mechanism has been explained in terms of metal to oxide carrier injection at low copper thickness and metal layer conduction at higher Cu thicknesses. The peak transmittance of the films is 88% and the photopic averaged transmittance is 75%. Optical transmission behavior of the films involves absorption by copper due to d-band to Fermi-surface transitions at short wavelengths and reflectance combined with scattering losses at long wavelengths. A Burstein-Moss shift in the band gap of the films is seen to take place with increase in thickness of the copper layer. The Haacke figure of merit has been calculated for the films with the best value being 8.7x10{sup -3} OMEGA{sup -1}. Pole figure results reveal that the copper midlayer acts as a hindrance to (002) ZnO texturing rather than as a seed layer. These results also confirm the mechanism of conduction. The results of the study assume further significance because annealing at 150 deg. C for up tomore » 24 h in a reducing (Ar+5% H{sub 2}) ambient was found to have negligible effect on the properties of the films.« less

Authors:
;  [1];  [2];  [3]
  1. School of Materials and Flexible Display Center, Arizona State University, Tempe, Arizona 85287 (United States)
  2. Silicon Technology Solutions, Freescale Semiconductor Inc., Tempe, Arizona 85284 (United States)
  3. Physical Electronics, Chanhassen, Minnesota 55317 (United States)
Publication Date:
OSTI Identifier:
21361832
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 106; Journal Issue: 6; Other Information: DOI: 10.1063/1.3213385; (c) 2009 American Institute of Physics; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ANNEALING; CARRIER DENSITY; COPPER; DEPOSITION; ELECTRIC CONDUCTIVITY; FERMI LEVEL; HALL EFFECT; HYDROGEN; LAYERS; REFLECTIVITY; SEMICONDUCTOR MATERIALS; SPUTTERING; TEXTURE; THICKNESS; THIN FILMS; ZINC OXIDES; CHALCOGENIDES; DIMENSIONS; ELECTRICAL PROPERTIES; ELEMENTS; ENERGY LEVELS; FILMS; HEAT TREATMENTS; MATERIALS; METALS; NONMETALS; OPTICAL PROPERTIES; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; SORPTION; SURFACE PROPERTIES; TRANSITION ELEMENTS; ZINC COMPOUNDS

Citation Formats

Sivaramakrishnan, K., Alford, T. L., Theodore, N. D., and Moulder, J. F. The role of copper in ZnO/Cu/ZnO thin films for flexible electronics. United States: N. p., 2009. Web. doi:10.1063/1.3213385.
Sivaramakrishnan, K., Alford, T. L., Theodore, N. D., & Moulder, J. F. The role of copper in ZnO/Cu/ZnO thin films for flexible electronics. United States. doi:10.1063/1.3213385.
Sivaramakrishnan, K., Alford, T. L., Theodore, N. D., and Moulder, J. F. Tue . "The role of copper in ZnO/Cu/ZnO thin films for flexible electronics". United States. doi:10.1063/1.3213385.
@article{osti_21361832,
title = {The role of copper in ZnO/Cu/ZnO thin films for flexible electronics},
author = {Sivaramakrishnan, K. and Alford, T. L. and Theodore, N. D. and Moulder, J. F.},
abstractNote = {ZnO/Cu/ZnO multilayer structures with very high conductivity have been obtained by magnetron sputtering. The Hall resistivity of the films was as low as 6.9x10{sup -5} OMEGA-cm with a carrier concentration of 1.2x10{sup 22} cm{sup -3} at the optimum copper layer thickness. The conduction mechanism has been explained in terms of metal to oxide carrier injection at low copper thickness and metal layer conduction at higher Cu thicknesses. The peak transmittance of the films is 88% and the photopic averaged transmittance is 75%. Optical transmission behavior of the films involves absorption by copper due to d-band to Fermi-surface transitions at short wavelengths and reflectance combined with scattering losses at long wavelengths. A Burstein-Moss shift in the band gap of the films is seen to take place with increase in thickness of the copper layer. The Haacke figure of merit has been calculated for the films with the best value being 8.7x10{sup -3} OMEGA{sup -1}. Pole figure results reveal that the copper midlayer acts as a hindrance to (002) ZnO texturing rather than as a seed layer. These results also confirm the mechanism of conduction. The results of the study assume further significance because annealing at 150 deg. C for up to 24 h in a reducing (Ar+5% H{sub 2}) ambient was found to have negligible effect on the properties of the films.},
doi = {10.1063/1.3213385},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 6,
volume = 106,
place = {United States},
year = {2009},
month = {9}
}