1070-4272/02/7507-1075$27.00C2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 7, 2002, pp. 1075!1078. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 7,
2002, pp. 1092!1095.
Original Russian Text Copyright + 2002 by Mamedov.
AND CORROSION PROTECTION OF METALS
Electrodeposition of Thin Lead!Tellurium Alloy Films
from Fluoroborate Electrolyte
M. N. Mamedov
Institute of Inorganic and Physical Chemistry, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan
Received October 23, 2001; in final form, March 2002
Abstract-Electrodeposition of lead!tellurium alloys from a fluoroborate electrolyte was studied. Cyclic
voltammetry was applied to determine the range of potentials of joint electrodeposition of Pb and Te to form
PbTe on the cathode.
Lead telluride, and also solid solutions on its base
in the form of thin films are widely used in various
fields of semiconductor industry to fabricate thermo-
electric transducers, thermoelements, and IR detectors
Thin films of metal chalcogenides, including PbTe,
are commonly obtained by vacuum evaporation .
This technique is labor-consuming, requires intricate
equipment, and involves use of high temperature.
Moreover, PbTe dissociates in evaporation into the
components, which commonly leads to its fractional
distillation and to deposition of compositionally in-
homogeneous films. Therefore, the electrochemical
technique has been frequently used recently for ob-
taining thin chalcogenide films [3, 4]. This method is
distinguished by simplicity, low material expenditure,
and possibility of easily controlling the composition
and thickness of the layers obtained.
The first electrochemical syntheses of lead telluride
were carried out in . The syntheses were based
on cathodic dissolution of tellurium and anodic dis-
solution of the metal whose telluride is being ob-
tained. In the process, interaction between Te
present in the electrolyte results in the formation
of PbTe powder on the electrolyzer bottom.
In , thin layers of lead3tellurium alloy were ob-
tained by cathodic deposition from a simple nitrate
electrolyte containing Pb(NO
it is known  that high-quality cathodic deposits
cannot be always obtained from simple electrolytes,
especially in those cases when the standard potentials
of the metals being codeposited are strongly different.
The standard potential of the Te/[TeOOH]
in acid media is +0.551 V, and that of the Pb/Pb
couple is 30.126 V. The difference of the standard
potentials is 0.677 V.
To make closer the potentials of tellurium and lead
deposition, such complex electrolytes were used in
which tellurium forms more stable complex ions than
lead. In this study, as such an electrolyte we used a
fluoroborate lead-plating solution of the composition
joiner’s glue 1.0 (electrolyte no. 1) . In electrolyte
no. 1, lead deposition occurs without any noticeable
hindrance, whereas in fluorine-containing media, tel-
lurium is present as a complex anion [Te(OH)
, with Te(OH)
ions formed in its dissociation
directly involved in the cathodic discharge. According
to , the discharge of Te(OH)
ions occurs in
stages, with each stage of formation of intermediates
characterized by a certain equilibrium potential, which
becomes more negative in reduction processes. This
may also make closer the deposition potentials of tel-
lurium and lead.
The electrolysis was performed and polarization
curves were measured in a poly(methyl methacrylate)
cell. Platinum electrodes coated with tellurium, lead,
and tellurium3lead alloy (up to 5 mm) served as cath-
odes, and platinum plate, as anode. The polarization
curves were measured in the potentiodynamic mode
at a potential sweep rate of 8 mV s
with a P-5827M
potentiostat and a PDP4-003 self-recorder. As refer-
ence served saturated silver chloride electrode. The
potentials measured were recalculated to the hydrogen
to be added to the lead-plating electrolyte
was preliminarily dissolved in HF, since TeO