Structure and Phase Composition Study of Heavy Doped with Carbon Thin Films of TiO2 : C Deposited by RF Magnetron Sputtering

• Published in: Russian journal of inorganic chemistry 2022-10, Vol.67 (10), p.1509-1520
• Main Authors: Milenov, T., Terziyska, P., Avdeev, G., Karashanova, D., Georgieva, B., Avramova, I., Genkov, K., Valcheva, E.
• Format: Article
• Language: English
• Subjects: Anatase; Annealing; Brookite; Carbon; Carbon content; Chemistry; Chemistry and Materials Science; Ellipsometry; Glass substrates; Heat treatment; Inorganic Chemistry; Low temperature; Magnetron sputtering; Nanocrystals; Phase composition; Photoelectrons; Plates; Process parameters; Raman spectroscopy; Rutile; Spectrum analysis; Synthesis and Properties of Inorganic Compounds; Thickness; Thin films; Titanium dioxide; X ray photoelectron spectroscopy
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023622100333

The aim of the present research is to study some aspects of the carbon doping of TiO 2 thin films and the influence of low temperature thermal annealing on the phase precipitation in thin films. Тhin films of heavily doped with carbon TiO 2 (up to 3 at % C) were deposited on (15 × 25 × 1 mm) glass substrates by r.f. magnetron co-sputtering of TiO 2 target and carbon plates on its erosion zone in Ar + air (residual pressure of 0.5 and 0.6 Pa, respectively) atmosphere. Two different process’s parameters were varied in different experiments in order to change the carbon content: the total area of the carbon plates which was 30, 84, 132, 400 and 830 mm 2 ) and the radial distance between the center of the circle of the erosion zone with maximum rate of sputtering which was 2 and 4 cm. The as-deposited and annealed (air, 400°C, 1h) thin films with thickness of 110–150 nm were studied by ellipsometry, grazing incidence X-ray diffractometry (GIXRD), X-ray photoelectron spectroscopy, Raman spectroscopy, transmission and scanning electron microscopies. The GIXRD patterns reveal a mix of amorphous and nanocrystalline anatase and rutile TiO 2 phases for all thin films. The Raman study confirms this conclusion but the TEM and GIXRD studies show presence of non-stoichiometric nanocrystalline phase based on Ti 3 C 20 O 14 together with the other phases of TiO 2 -anatase, rutile and brookite. Similar charcterizations were carried out after annealing at 400°C in air for 60 min and the most prominent effects of thermal treatment are discussed .