Studies on the room temperature growth of nanoanatase phase TiO2 thin films by pulsed dc magnetron with oxygen as sputter gas

Abstract

Electrical and optical properties of Nb-doped TiO 2 films deposited by dc magnetron sputtering using slightly reduced Nb-doped TiO 2 − x ceramic targets J. Vac. Sci. Technol. A 28, 851 (2010); 10.1116/1.3358153 Influence of substrate temperature on growth of nanocrystalline silicon carbide by reactive magnetron sputtering J. Appl. Phys. 98, 024313 (2005); 10.1063/1.1985975Influence of working gas pressure on structure and properties of WO 3 films reactively deposited by rf magnetron sputtering J.The anatase phase titanium dioxide ͑TiO 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 4.5ϫ 10 −2 mbar are nanocrystalline ͑grain size of 28-43 nm͒ with anatase phase. The films deposited at the chamber pressure of 7.2ϫ 10 −2 mbar are found to be highly crystalline with a direct optical band gap of 3.40 eV, refractive index of 2.54 ͑at = 400 nm͒, and work function of 4.77 eV ͑determined by the Kelvin probe measurements͒. From the optical emission spectra of the plasma and transport of ions in matter calculations, we find that the crystallization of TiO 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 + , TiO 2 + , and O 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 7.2ϫ 10 −2 mbar was studied for its electrochromic properties by protonic intercalation. It showed good electrochromic behavior with an optical modulation of ϳ45%, coloration efficiency of 14.7 cm 2 C −1 , and switching time ͑t c ͒ of 50 s for a 2 ϫ 2 cm 2 device at = 633 nm.

Development of microfabricated TiO2 channel waveguides

“…Similar features were reported for TiO 2 films deposited by sputtering. [15][16][17][18][19][20][21] The refractive index at 500 nm in Fig. 2(b) is 2.49, which is in good agreement with a TiO 2 film prepared under a low pressure condition.…”

Measured density of copper atoms in the ground and metastable states in argon magnetron discharge correlated with the deposition rate

“…Magnetron discharges are widely used for thin film deposition in surface treatment 1, 2 , magnetic and superconducting devices 3 , semiconductor industry 4 and in surface coating engineering of materials under low temperature conditions 5,6 . In these systems, the magnetic field, usually produced by placing permanent magnets behind the cathode, confines the plasma in the near cathode region, reducing the electron loss to the sidewalls.…”

A comprehensive study of the influence of the stoichiometry on the physical properties of TiOx films prepared by ion beam deposition

“…[1][2][3][4][5][6][7][8][9][10] The use of TiO 2 powders or films is potentially important in the attempts to solve some environmental and energy problems. 11 Moreover, TiO 2 coatings improve surface hardness and wear resistance.…”