ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 12, pp. 2051–2055. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © V.V. Antipov, A.P. Belyaev, A.A. Malygin, V.P. Rubets, E.A. Sosnov, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81,
No. 12, pp. 1937–1941.
Effect of the Substrate Nature on the Formation
of Thin Titanium Dioxide Films by Molecular Layering
V. V. Antipov, A. P. Belyaev, A. A. Malygin, V. P. Rubets, and E. A. Sosnov
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received July 11, 2008
Abstract—Results of structural studies of titanium dioxide films synthesized on glass, silicon, and mica
substrates by molecular layering are presented. An analysis of data furnished by electron and X-ray diffraction
analyses and atomic-force microscopy of the samples in different growth stages revealed the effect of the substrate
nature on the structure of the titanium oxide coatings synthesized.
Finding the factors that affect the structure of tita-
nium oxide films formed by molecular layering (ML)
is of not only theoretical, but also practical interest. It
is known that titanium dioxide finds use in optical,
pigment, catalytic, sorption, etc. coatings [1–9]. De-
pending on the functional purpose, and important fac-
tor is the phase state of titanium dioxide, which can be
in the form of anatase, rutile, and brookite.
As shown by previous studies, the substrate nature
strongly affects the phase composition of the nanolayer
being formed in synthesis of titanium oxide nanostruc-
tures on the surface of porous silicon and aluminum
oxide particles [2, 3]. The surface of aluminum oxide
favors formation of a rutile-like modification of tita-
nium oxide, whereas on silicon dioxide, mostly an ana-
tase-like system is produced.
A study of the properties of ML products revealed
such structural-dimensional characteristics as effects of
a monolayer, substrate coverage, and structural match-
ing between the substrate surface and layer being
grown [2, 7, 8]. It can be assumed that, as the thickness
of a growing layer increases, the substrate will exert
lesser influence on its structure, but in the initial stages
of synthesis, in a thin (several monolayers) coating, the
matrix is known to have the most pronounced effect
(monolayer effect). In turn, the structure of the coating
formed in the initial stages of synthesis, can affect that
of thicker layers.
The initial stages of synthesis of titanium oxide
nanolayers on the surface of semiconductor silicon and
glass by the ML method, with up to 20 treatment cy-
cles, have been studied by ellipsometry and atomic-
force microscopy (AFM) [1, 7, 8, 10, 11]. At the same
time, integrated studies of thicker (with several hun-
dreds or thousands of treatment cycles, which provides
film thicknesses of 100 nm and more) titanium oxide
layers, their phase composition on the surface of vari-
ous substrates, and the influence exerted by the matrix
nature on the structure of coatings being formed have
not been widely reported in scientific publications.
The aim of this study was to examine the influ-
ence exerted by the nature of the solid-phase matrix
(glass, mica, silicon) on the structure of the titanium
oxide layer formed on the substrate surface in molecular
layering (beginning with 500 treatment cycles and more).
As substrates were used plates (20
20 mm) of
polished sodium-calcium-silicate glass, Si(III) silicon,
and mica (muscovite), treated, prior to synthesis, with
a surfactant [CH
Na + 0.5 wt % NaOH] and
then washed with distilled water and dried in a vacuum
at 500 K for 15 min.
The fact that the silicon surface commonly con-
tains a thin (up to several nanometers) layer of silicon
oxide and results of an analysis of published data sug-
gest that hydroxy groups bonded to silicon atoms are
the main reaction centers on the surface of substrates
treated with water and dried.
The synthesis was performed by alternate treat-
ments of the starting matrices with TiCl
pors, followed by removal of the excess amount of
the starting reagent and gaseous reaction products to
a residual pressure in the reactor of ≤1 Pa.
INORGANIC SYNTHESIS AND INDUSTRIAL