766
GAPANOVICH et al.
was relatively low in all of the samples. From linear resistance increases with increasing ZnS concentra-
portions (dashed lines) of their current–voltage tion, because ZnS is a high-resistivity material.
curves, we evaluated the series electrical resistance R
of the samples (Fig. 5, Table 3). The electrical resis-
tance, an important characteristic of an absorbing
ACKNOWLEDGMENTS
layer, increases with increasing ZnS concentration in
the samples. The reason for this is that zinc sulfide is a
high-resistivity material. Also shown in Fig. 5 is the
current–voltage curve of Cu1.85ZnSnS4 (sample 8)
prepared by direct synthesis from binary sulfides,
without KI in the starting mixture. The R of this sam-
ple is 160 Ω (Table 3).
This work was supported by the Russian Federation
Ministry of Education and Science (agreement no.
14.613.21.0065; unique identifier of the project:
RFMEF161317X0065).
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CONCLUSIONS
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If the starting mixture contains no sulfur, SnS is
formed as
a
second phase, along with
a
Cu1.5Zn1.15Sn0.85S4-based phase. At a high potassium
iodide concentration in the starting mixture (nKI = 5),
no SnS is formed during Cu1.5Zn1.15Sn0.85S4 or
Cu1.85ZnSnS4 synthesis.
Thus, we have found conditions for the synthesis of
Cu1.5Zn1.15Sn0.85S4 and Cu1.85ZnSnS4 solid solutions
free of ZnS and SnS inclusions. The present results
can be useful for optimizing the synthesis of mono-
grain CZTS powders for the fabrication of membrane
solar cells.
Cu1.5Zn1.15Sn0.85S4 and Cu1.85ZnSnS4 have been
shown to be p-type semiconductors. Their electrical
Translated by O. Tsarev
INORGANIC MATERIALS
Vol. 54
No. 8
2018