Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis
Photo- and electroluminescence properties of ZnS obtained using selfpropagating high-temperature synthesis and doped with Cu were studied in this work. It has been shown that high-temperature one-stage synthesis enables to obtain two-phase system ZnS-Cu₂₋xS with the maximum radiation 515 nm for phot...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2015
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| Цитувати: | Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis / Yu.Yu. Bacherikov, A.G. Zhuk, O.B. Okhrimenko, D.L. Kardashov, S.V. Kozitskiy // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 3. — С. 309-311. — Бібліогр.: 8 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-1212032025-02-09T20:56:54Z Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis Bacherikov, Yu.Yu. Zhuk, A.G. Okhrimenko, O.B. Kardashov, D.L. Kozitskiy, S.V. Photo- and electroluminescence properties of ZnS obtained using selfpropagating high-temperature synthesis and doped with Cu were studied in this work. It has been shown that high-temperature one-stage synthesis enables to obtain two-phase system ZnS-Cu₂₋xS with the maximum radiation 515 nm for photo- and electroluminescence. Since the synthesis process is non-equilibrium, impurities distribute nonuniformly in the bulk of microcrystals. Additional annealing and introducing the Ga coactivator lead to more non-uniform distribution of impurities in the bulk of microcrystals. It causes the increase in the intensity of the blue band in photoluminescence spectra and shift of the maximum of electroluminescence toward longer wavelengths. It is probable that this increase in the intensity of the blue band in photoluminescence spectra is caused by formation of the radiative centers Cui₋CuZn. 2015 Article Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis / Yu.Yu. Bacherikov, A.G. Zhuk, O.B. Okhrimenko, D.L. Kardashov, S.V. Kozitskiy // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 3. — С. 309-311. — Бібліогр.: 8 назв. — англ. 1560-8034 DOI: 10.15407/spqeo18.03.309 PACS 78.55.Et, 78.60.Fi https://nasplib.isofts.kiev.ua/handle/123456789/121203 en Semiconductor Physics Quantum Electronics & Optoelectronics application/pdf Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Photo- and electroluminescence properties of ZnS obtained using selfpropagating high-temperature synthesis and doped with Cu were studied in this work. It has been shown that high-temperature one-stage synthesis enables to obtain two-phase system ZnS-Cu₂₋xS with the maximum radiation 515 nm for photo- and electroluminescence. Since the synthesis process is non-equilibrium, impurities distribute nonuniformly in the bulk of microcrystals. Additional annealing and introducing the Ga coactivator lead to more non-uniform distribution of impurities in the bulk of microcrystals. It causes the increase in the intensity of the blue band in photoluminescence spectra and shift of the maximum of electroluminescence toward longer wavelengths. It is probable that this increase in the intensity of the blue band in photoluminescence spectra is caused by formation of the radiative centers Cui₋CuZn. |
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Article |
| author |
Bacherikov, Yu.Yu. Zhuk, A.G. Okhrimenko, O.B. Kardashov, D.L. Kozitskiy, S.V. |
| spellingShingle |
Bacherikov, Yu.Yu. Zhuk, A.G. Okhrimenko, O.B. Kardashov, D.L. Kozitskiy, S.V. Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Bacherikov, Yu.Yu. Zhuk, A.G. Okhrimenko, O.B. Kardashov, D.L. Kozitskiy, S.V. |
| author_sort |
Bacherikov, Yu.Yu. |
| title |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis |
| title_short |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis |
| title_full |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis |
| title_fullStr |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis |
| title_full_unstemmed |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis |
| title_sort |
electroluminescence powdered zns:cu obtained by one-stage synthesis |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2015 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/121203 |
| citation_txt |
Electroluminescence powdered ZnS:Cu obtained by one-stage synthesis / Yu.Yu. Bacherikov, A.G. Zhuk, O.B. Okhrimenko, D.L. Kardashov, S.V. Kozitskiy // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 3. — С. 309-311. — Бібліогр.: 8 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
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| first_indexed |
2025-11-30T16:57:22Z |
| last_indexed |
2025-11-30T16:57:22Z |
| _version_ |
1850235257796689920 |
| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 3. P. 309-311.
doi: 10.15407/spqeo18.03.309
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
309
PACS 78.55.Et, 78.60.Fi
Electroluminescence powdered ZnS:Cu obtained
by one-stage synthesis
Yu.Yu. Bacherikov1*, A.G. Zhuk1, O.B. Okhrimenko1, D.L. Kardashov2, S.V. Kozitskiy2
1V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine
41, prospect Nauky, 03028 Kyiv, Ukraine; *e-mail: Yuyu@isp.kiev.ua
2Odessa National Maritime Academy, 8, Didrikhson str., 65029 Odessa, Ukraine
Abstract. Photo- and electroluminescence properties of ZnS obtained using self-
propagating high-temperature synthesis and doped with Cu were studied in this work. It
has been shown that high-temperature one-stage synthesis enables to obtain two-phase
system ZnS-Cu2–xS with the maximum radiation 515 nm for photo- and electro-
luminescence. Since the synthesis process is non-equilibrium, impurities distribute non-
uniformly in the bulk of microcrystals. Additional annealing and introducing the Ga co-
activator lead to more non-uniform distribution of impurities in the bulk of microcrystals.
It causes the increase in the intensity of the blue band in photoluminescence spectra and
shift of the maximum of electroluminescence toward longer wavelengths. It is probable
that this increase in the intensity of the blue band in photoluminescence spectra is caused
by formation of the radiative centers Cui-CuZn.
Keywords: electroluminescence, photoluminescence, zinc sulfide, self-propagating high-
temperature synthesis.
Manuscript received 08.04.15; revised version received 10.06.15; accepted for
publication 03.09.15; published online 30.09.15.
1. Introduction
Recently, luminophors are being increasingly used in
various semiconductor devices and information displays.
Basic requirements for luminescent light sources are
effective conversion of exciting radiation energy into the
visible light energy, stable radiation in a given spectral
range and low power consumption. One of the most
technologically simple devices based on the
phenomenon of electroluminescence (EL) is an electro-
luminescent capacitor based on powder electro-
luminophors. The advantage of these devices lies in the
possibility to create them flexible, which allows
expanding their application field.
One of the conditions, under which glowing
electroluminophors activated with copper is possible at
excitation with alternating electric field, is the existence
of another phase inclusions in luminophor material,
which allows creation of conditions for concentration of
the field in thin layers of the sample. In ZnS-based
electroluminophors, this condition is fulfilled by
introducing a high concentration of copper
(approximately 10–3 g of Cu per 1 g of ZnS).
As it was ascertained in [1], for radiative
recombination in semiconductors, in addition to
recombination centers, it takes free electrons and holes,
generation of which occurs through the existence of
surface phase. In zinc-sulfide electroluminophors, the
surface phase is copper sulfide, so excitation of
electroluminophors is a number of processes of injection
and multiplication of charge carriers in the hetero-
junction ZnS-Cu2–xS. The bandgap of Cu2–xS is much
smaller and conductivity is much higher than those in
ZnS, that’s why many researchers identify this contact
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 3. P. 309-311.
doi: 10.15407/spqeo18.03.309
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
310
with the Mott-Schottky type contact [2, 3]. Depending
on the ratios of the electron affinity energies, location of
the Fermi levels and extent of doping materials forming
heterojunctions Cu2–xS-ZnS:Cu, their energy diagrams
and character of current flow will be different.
Whereas self-propagating high-temperature
synthesis (SHS) is a low-cost technology, the use of this
method allows to reduce the price obtained material.
Besides, non-equilibrium of crystallization process
allows obtaining the samples doped with impurities,
concentration of which exceeds the equilibrium one [4].
Therefore, the possibility to obtain electroluminophors
based on ZnS by using SHS method is an urgent task.
The aim of this work was to study the possibility of
getting electroluminophor ZnS:Cu by using the SHS
method as well as to determine the effect of Ga impurity
and subsequent thermal treatments on its spectral
characteristics.
2. Experimental technique
The modes of synthesis were chosen in such a manner
that allowed obtaining powdered ZnS doped with
different impurities. For the samples synthesized by us,
the content of starting materials was: Zn – 0.45 mole, S
– 0.56 mole, CuCl – 0.06 mole, Ga – 0.0025 mole.
Thermal annealing at 800 °C was performed in a
laboratory silica furnace. Introduction of atmosphere
gases to the annealed powder was limited by a gas gate
of granular coal. The temperature mode of annealing
process was controlled with a thermocouple, located in
the area of annealed material. The annealing time was
120 min.
The spectra of photoluminescence (PL) and
electroluminescence (EL) were measured using the
facility SDL-2 at room temperature. Excitation of PL
was carried out using radiation of the nitrogen laser
LHI-21 (λ = 337.1 nm), and EL – alternating sinusoidal
voltage (U = 0…300 V, f = 100…5000 Hz). To
investigate EL, we used the device for express analysis
of luminophors, as described in [5].
3. Experimental results and discussion
Photoluminescence spectra of powdered ZnS:Cu,Cl and
ZnS:Cu,Ga synthesized by SHS method are presented in
Fig. 1. The amount of copper introduced into furnace
charge was sufficient for doping ZnS and formation of
the phase Cu2S necessary for creating the heterojunction
Cu2–xS-ZnS. As shown in Fig. 1, the PL spectra are quite
different from each other. If the PL spectrum for the
powder ZnS:Cu,Cl is a broad band in the blue-green
spectral range with λmax ~ 515 nm, the PL spectra for
ZnS:Cu,Ga before and after annealing consist of two
broad bands with λmax ~ 440…450 nm and λmax ~
515…535 nm. The difference between the PL spectra of
ZnS:Cu, Ga before and after annealing is revealed in the
ratio of intensities of blue and green bands.
Fig. 2 shows the EL spectra for powders ZnS:Cu,Cl
(curve 1) and ZnS:Cu,Ga (curve 2) as well as
ZnS:Cu,Ga annealed at 400 °C (curve 3). As shown in
Fig. 2, the EL spectra have the form of broad bands in
the blue-green spectral range with the peaks at
λmax ~515 nm, ~525 nm, ~535 nm, respectively, for the
curves 1, 2 and 3. Thus, introduction of Ga leads to
flaring up the blue PL band and shifting the green band
into the long-wave side. Additional annealing of
ZnS:Cu,Ga led to further strong increasing the blue EL
band and shifting the green band into the long-wave
side. Additional annealing after synthesis leads to a more
uniform distribution of Cu impurities in material,
including that over the phase Cu2–xS. Annealing also
promotes more active introduction of copper into lattice
sites, the availability of co-activator Ga also contributes
to this process. But account must be taken of that the
synthesis of material occurs in a relatively short period
of time (several minutes), and the temperature in this
time period ranges from 300 up to 2500…3000 K.
Therefore, the impurity distribution, ratio of phases etc.
are the result of non-equilibrium conditions for synthesis
of material.
350 400 450 500 550 600 650 700
0.0
0.2
0.4
0.6
0.8
1.0
PL
(a
rb
. u
n.
)
λ, nm
1
2
3
Fig. 1. Photoluminescence spectra of luminophors ZnS:Cu,Cl (1)
and ZnS:Cu,Ga (2) as well as luminophor ZnS:Cu,Ga annealed
at 400 °C (3). λ = 337.1 nm of the nitrogen laser LHI-21.
400 450 500 550 600 650 700
0.0
0.2
0.4
0.6
0.8
1.0 1
2
3
E
L
(a
rb
. u
n.
)
λ, nm
Fig. 2. EL spectra of luminophors ZnS:Cu,Cl (1) and
ZnS:Cu,Ga (2) as well as luminophor ZnS:Cu,Ga annealed at
400 °C (3).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 3. P. 309-311.
doi: 10.15407/spqeo18.03.309
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
311
Effect of Ga as a co-activator on the spectral
composition and intensity of PL is related with the need
to compensate the charge of internal defects in material,
which is described in many details in [6-8]. In [8], it was
shown that even a small amount of Ga impurities in ZnS
promotes introducing copper into specific sites of
sublattice or filling Zn vacancies, which leads to
increasing contribution of the green band in the
luminescence spectrum. The appearance of the blue band
in the PL spectrum when introducing Ga (Fig. 1, curves
2 and 3) is related, apparently, with formation of centers
of close DA pair of the Cui-CuZn type.
The increase in intensity of the blue band (Fig. 1,
curve 3) is likely related with redistribution of copper
impurity in the bulk of microcrystals. And the presence
of Ga as co-activator, which along with copper fills the
place in the cation sublattice, leads to additional
association of copper ions and formation of centers of
close DA pair of the Cui-CuZn type and, accordingly, to
the increase in the blue band of photoluminescence.
4. Conclusions
As seen from the results, the SHS method enables to
obtain two-phase systems. Account must be taken that
SHS is non-equilibrium process, which leads to non-
uniform distribution of impurities and simultaneous
formation of different phases of the obtained material.
Considering the peculiarities of synthesis and need to
obtain two phases, copper was introduced in some
excess amount during the process of preparing the
furnace charge. The excess is necessary, on the one
hand, for doping of zinc sulfide, and on the other hand,
for formation of the phase Cu2–xS.
References
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P.S. Chowdhary, The electroluminescence (EL)
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