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Title: Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas

Abstract

The anatase phase titanium dioxide (TiO{sub 2}) thin films were deposited at room temperature by pulsed dc magnetron sputtering using pure oxygen as sputter gas. The structural, optical, electrical, and electrochromic properties of the films have been studied as a function of oxygen pressure in the chamber. The x-ray diffraction results indicate that the films grown above 4.5x10{sup -2} mbar are nanocrystalline (grain size of 28-43 nm) with anatase phase. The films deposited at the chamber pressure of 7.2x10{sup -2} mbar are found to be highly crystalline with a direct optical band gap of 3.40 eV, refractive index of 2.54 (at {lambda}=400 nm), and work function of 4.77 eV (determined by the Kelvin probe measurements). From the optical emission spectra of the plasma and transport of ions in matter calculations, we find that the crystallization of TiO{sub 2} at room temperature is due to the impingement of electrons and ions on the growing films. Particularly, the negative oxygen ions reflected from the target by 'negative ion effects' and the enhanced density of TiO, TiO{sup +}, TiO{sub 2}{sup +}, and O{sup 2+} particles in the plasma are found to improve the crystallization even at a relatively low temperature. From an applicationmore » point of view, the film grown at 7.2x10{sup -2} mbar was studied for its electrochromic properties by protonic intercalation. It showed good electrochromic behavior with an optical modulation of {approx}45%, coloration efficiency of 14.7 cm{sup 2} C{sup -1}, and switching time (t{sub c}) of 50 s for a 2x2 cm{sup 2} device at {lambda}=633 nm.« less

Authors:
;  [1]
  1. Semiconductor Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)
Publication Date:
OSTI Identifier:
20982775
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 6; Other Information: DOI: 10.1063/1.2714770; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANIONS; CRYSTAL GROWTH; CRYSTALLIZATION; DEPOSITION; ELECTROCHROMISM; EMISSION SPECTRA; EV RANGE 01-10; GRAIN SIZE; MAGNETRONS; NANOSTRUCTURES; OXYGEN; OXYGEN IONS; REFRACTIVE INDEX; SEMICONDUCTOR MATERIALS; SPUTTERING; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; TITANIUM OXIDES; WORK FUNCTIONS; X-RAY DIFFRACTION

Citation Formats

Karuppasamy, A., and Subrahmanyam, A. Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas. United States: N. p., 2007. Web. doi:10.1063/1.2714770.
Karuppasamy, A., & Subrahmanyam, A. Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas. United States. doi:10.1063/1.2714770.
Karuppasamy, A., and Subrahmanyam, A. Thu . "Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas". United States. doi:10.1063/1.2714770.
@article{osti_20982775,
title = {Studies on the room temperature growth of nanoanatase phase TiO{sub 2} thin films by pulsed dc magnetron with oxygen as sputter gas},
author = {Karuppasamy, A. and Subrahmanyam, A.},
abstractNote = {The anatase phase titanium dioxide (TiO{sub 2}) thin films were deposited at room temperature by pulsed dc magnetron sputtering using pure oxygen as sputter gas. The structural, optical, electrical, and electrochromic properties of the films have been studied as a function of oxygen pressure in the chamber. The x-ray diffraction results indicate that the films grown above 4.5x10{sup -2} mbar are nanocrystalline (grain size of 28-43 nm) with anatase phase. The films deposited at the chamber pressure of 7.2x10{sup -2} mbar are found to be highly crystalline with a direct optical band gap of 3.40 eV, refractive index of 2.54 (at {lambda}=400 nm), and work function of 4.77 eV (determined by the Kelvin probe measurements). From the optical emission spectra of the plasma and transport of ions in matter calculations, we find that the crystallization of TiO{sub 2} at room temperature is due to the impingement of electrons and ions on the growing films. Particularly, the negative oxygen ions reflected from the target by 'negative ion effects' and the enhanced density of TiO, TiO{sup +}, TiO{sub 2}{sup +}, and O{sup 2+} particles in the plasma are found to improve the crystallization even at a relatively low temperature. From an application point of view, the film grown at 7.2x10{sup -2} mbar was studied for its electrochromic properties by protonic intercalation. It showed good electrochromic behavior with an optical modulation of {approx}45%, coloration efficiency of 14.7 cm{sup 2} C{sup -1}, and switching time (t{sub c}) of 50 s for a 2x2 cm{sup 2} device at {lambda}=633 nm.},
doi = {10.1063/1.2714770},
journal = {Journal of Applied Physics},
number = 6,
volume = 101,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}