Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures
New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of a luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°C. It was established that the f...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2004
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| Назва видання: | Semiconductor Physics Quantum Electronics & Optoelectronics |
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| Цитувати: | Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures / G.S. Svechnikov, L.V. Zavyalova, N.N. Roshchina, I.V. Prokopenko, L.I. Berezhinsky, V.S. Khomchenko, O.S. Litvin // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 157-160. — Бібліогр.: 12 назв. — англ. |
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irk-123456789-1181662017-05-30T03:03:13Z Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures Svechnikov, G.S. Zavyalova, L.V. Roshchina, N.N. Prokopenko, I.V. Berezhinsky, L.I. Khomchenko, V.S. Litvin, O.S. New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of a luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°C. It was established that the film emission maximum monotonously shifts into short-wave spectral region at the decreasing substrate temperature: from 590 nm (Ts = 120°C) to 500 nm (Ts = 50°C) for ZnS and from 510 nm (Ts = 120°C) to 450 nm (Ts = 40°C) for CdS. This fact can be explained by the quantum size effect: X-ray analysis has shown that researched films contain crystalline particles of 1…5 nm size. 2004 Article Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures / G.S. Svechnikov, L.V. Zavyalova, N.N. Roshchina, I.V. Prokopenko, L.I. Berezhinsky, V.S. Khomchenko, O.S. Litvin // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 157-160. — Бібліогр.: 12 назв. — англ. 1560-8034 PACS: 81.15.G, 68.55.J, 61.66 http://dspace.nbuv.gov.ua/handle/123456789/118166 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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English |
| description |
New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of a luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°C. It was established that the film emission maximum monotonously shifts into short-wave spectral region at the decreasing substrate temperature: from 590 nm (Ts = 120°C) to 500 nm (Ts = 50°C) for ZnS and from 510 nm (Ts = 120°C) to 450 nm (Ts = 40°C) for CdS. This fact can be explained by the quantum size effect: X-ray analysis has shown that researched films contain crystalline particles of 1…5 nm size. |
| format |
Article |
| author |
Svechnikov, G.S. Zavyalova, L.V. Roshchina, N.N. Prokopenko, I.V. Berezhinsky, L.I. Khomchenko, V.S. Litvin, O.S. |
| spellingShingle |
Svechnikov, G.S. Zavyalova, L.V. Roshchina, N.N. Prokopenko, I.V. Berezhinsky, L.I. Khomchenko, V.S. Litvin, O.S. Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Svechnikov, G.S. Zavyalova, L.V. Roshchina, N.N. Prokopenko, I.V. Berezhinsky, L.I. Khomchenko, V.S. Litvin, O.S. |
| author_sort |
Svechnikov, G.S. |
| title |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures |
| title_short |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures |
| title_full |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures |
| title_fullStr |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures |
| title_full_unstemmed |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures |
| title_sort |
composite film structures containg zns, cds nanoparticles prepared by moc pyrolysis at low temperatures |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2004 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/118166 |
| citation_txt |
Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures / G.S. Svechnikov, L.V. Zavyalova, N.N. Roshchina, I.V. Prokopenko, L.I. Berezhinsky, V.S. Khomchenko, O.S. Litvin // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2004. — Т. 7, № 2. — С. 157-160. — Бібліогр.: 12 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| work_keys_str_mv |
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2025-07-08T13:29:50Z |
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2025-07-08T13:29:50Z |
| _version_ |
1837085646178484224 |
| fulltext |
157© 2004, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
Semiconductor Physics, Quantum Electronics & Optoelectronics. 2004. V. 7, N 2. P. 157-160.
1. Introduction
The development of new directions in semiconductors
physics and microelectronics based on size reduction of
crystallites in semiconductor materials down to several
nanometers has resulted in increase of light sources effi-
ciency for the given wavelength set and can be used at a
creation of more powerful computing devices.
In this connection, it seems very actual to solve the
task of developing new technologies for fabrication of com-
posite nanocrystal structures, the research of their electro-
physical and optical characteristics, creation of photo-
sensitive and electroluminescent devices with improved
parameters in a wide range of spectral sensitivity on their
basis.
Several basic techniques are known to form nanocrystals
and composite layers containing them [1�5]. The most
widely known techniques are as follows: preparation of
colloidal solutions of nanocrystals by the condensation
method from a solution containing the semiconductor com-
ponents [3]; filling the nanosize cavities in ceolite by semi-
conductor clusters [4]; and also the method of a consecu-
tive ion implantation of semiconductor elements in Al2O3
matrix [5].
At the same time, the chemical method is known for
fabrication of semiconductor polycrystalline films of ZnS
and CdS, in particular. The method is based on pyrolysis of
chelate metalorganic compound (MOÑ) of zinc or cadmium
at the substrate temperature in the range 200�340°Ñ [6].
The purpose of the given work is the research oppor-
tunities to prepare composite layers based on ZnS and
CdS from chelate MOÑ of zinc and cadmium at the tem-
perature lower than 200°C. The morphology of film sur-
face, the X-ray spectra and photoluminescence spectra
were investigated to confirm nanocrystalline structure of
the composite film structures based on ZnS and CdS pre-
pared at various conditions.
2. Experimental procedure
Researched composite film structures were prepared by
a chemical method of spraying an ethanol solution of
chelate Zn- or Cd- MOC at the presence of polar solvent
(PS) on the heated substrate.
Chelate Zn- or Cd- MOÑ concern to a class ÌOÑ
with complex anion-ligands [7]. In this work, the follo-
wing compounds were used: with ligands containing
PACS: 81.15.G, 68.55.J, 61.66
Composite film structures containg ZnS, CdS
nanoparticles prepared by MOC pyrolysis
at low temperatures
G.S. Svechnikov, L.V. Zavyalova, N.N. Roshchina, I.V. Prokopenko, L.I. Berezhinsky,
V.S. Khomchenko, O.S. Lytvyn
V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
41, prospect Nauky, 03028 Kyiv, Ukraine, Phone: +380 (44) 265 64 77, (44) 265 73 51, (44)265 62 66,
fax: +380 (44) 265 83 42, E-mail: vsk@isp.kiev.ua
Abstract. New composite structures containing ZnS, CdS nanoparticles were prepared with
bright light-blue colour of luminescence. The structures were formed by spraying organic
solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range
40�120°Ñ. It was established that the film emission maximum monotonously shifts into
short-wave spectral region at the decreasing substrate temperature: from 590 nm (Òs = 120°Ñ)
to 500 nm (Òs = 50°Ñ) for ZnS and from 510 nm (Òs = 120°Ñ) to 450 nm (Òs = 40°Ñ) for CdS.
This fact can be explained by the quantum size effect: X-ray analysis has shown that re-
searched films contain crystalline particles of 1�5 nm size.
Keywords: nanocrystallite, ZnS, CdS, polymeric matrix, MOC pyrolysis, luminescence.
Paper received 12.03.04; accepted for publication 17.06.04.
158
SQO, 7(2), 2004
G.S. Svechnikov et al.: Composite film structures containg ZnS, CdS nanoparticles ...
sulfur, zinc and cadmium ditiocarbamates (dtc) [9], which
were applied by us in works [6,8,10], and later by au-
thors of work [11] for obtaining of CdS and CdZnS film.
The deposition of a ZnS- or CdS- based composite
film structures was carried out at atmospheric pressure in
a flowing non-sealed system. The substrates are placed
on a flat horizontal heater. The deposition was made by
compressed air at the pressure (0.6�1.2) ·105 Pà using a
spraying device fixed above the substrate. Films were
deposited for 5 to 20 minutes, and the film thickness was
0.5�1.0 microns depending on the deposition rate and
substrate temperature. The concentration of basic sub-
stance, dtc2Zn, [(C2H5)2NCS2]2Zn, or dtc2Cd,
[(C2H5)2NCS2]2Cd, consisted of 4 weight percents. It cor-
responds to solution of 0.1 M. The spraying rate was
1�2 ml/min. and the substrate temperature varied within
the limits 40�120°Ñ.
The surface morphology of the films was examined
with Nanoscope D3000 atomic force microscope (AFM)
(Digital Instruments). The crystal structure of films was
studied by X-ray diffraction analysis with a ÄÐÎÍ-3Ì
diffractometer (CuKα radiation). The photoluminescence
(PL) was excited by a nitrogen laser (λ = 337 nm).
3. Results and discussion
Thermal analysis of initial materials dtc2Zn and dtc2Cd
has shown that they have similar stages of material trans-
formation under the action temperature. However,
dtc2Zn all critical temperature points (melting, decom-
position and crystallization of decomposition products)
are 20 to 30°Ñ higher than those for dtc2Cd.
It was established that the polymeric substances are
formed for dtc2Cd of yellow colour or colorless for dtc2Zn
after heating at temperature 300°C (exceeding temperature
of decomposition). Polycrystalline powder is formed at tem-
peratures above 400�500°Ñ. It consists mainly of ZnS or
CdS as X-ray analysis showned. It is evidence of tem-
perature decomposition of dtc2Zn or dtc2Cd jointly with
a formation of particles ZnS or CdS in a polymeric ma-
trix. Such process availability allows obtaining the com-
posite material as a film.
To decrease the formation temperature of particles ZnS
or CdS in a polymeric matrix, the polar solvent (PS) was
inserted into initial solution. The PS presence should pro-
mote destruction of chemical bonds in dtc2Cd or dtc2Zn
molecules at lower temperatures.
The quality of films was investigated versus a relation-
ship of PS volume to the volume of ethanol solution of
dtc2Zn or dtc2Cd in a wide range: from 0.005 up to 1.000. It
was established that the films formed were of a good qual-
ity at the relationship about 0.01 only. Films were continu-
ous, homogeneous and with a minimal roughness. There
was it at temperature in the range 40�120°Ñ, instead of
~300°Ñ temperature in the absence of PS.
Thus, it is possible to believe that PS influencing on
initial substance plays a paramount role on the film forma-
tion at so low temperatures.
Apparently, the chemical bond of metal atom with
MOC elements except sulfur decreases at the introduc-
tion of PS into solution containing dtc2Zn or dtc2Cd. It
allows to considerably reduce the molecule decomposi-
tion temperatures. It is the most probable process that the
smallest ZnS or CdS particles are formated due to de-
struction of complex MOC molecules, since the metal
and sulfur in a molecule are tightly bound by the direct
and strong chemical bond. Other process of a matrix for-
mation has place from the rests of a dtc2Zn or dtc2Cd
molecules simultaneously.
The X-ray analysis of composite film structures pre-
pared from dtc2Cd at temperatures within the range
40�60°Ñ has shown that researched films contain crys-
talline structures with sizes 1�5 nm. It confirms the re-
sults of morphology surface investigations.
The complex structure of the prepared films was re-
vealed using AFM. The morphology of dtc2Cd film sur-
face is illustrated in Fig. 1. The films were prepared at
the temperature 60°Ñ. It is seen in Fig. 1 that against a
background basic of fine-grained film surface the embed-
ded grains are observed (sizes along the vertical direc-
tion are purposely 8-fold increased in comparison with
the horizontal one). The horizontal sizes of these sepa-
rate large grains change from 25 nm up to 1000 nm de-
pending on conditions of solution preparation and a
substrate temperature. The size of grains in the fine-
grained area of a surface amounts to 5 nm. The micro-
relief investigation of film grown at the various substrate
temperatures show that films with small sizes of grains
have grown at the substrate temperature of 40�60°Ñ and
with large grain sizes � at 100�120°Ñ. The similar be-
haviour is observed also for a composite structures ob-
tained from dtc2Zn.
The investigation of luminescence spectra has shown
that obtained composite structure containing ZnS and CdS
nanoparticles have rather bright luminescence. The spec-
tral location of luminescence maximum is connected with
conditions of preparing this material and, first of all,
with the temperature substrate.
0 2.
2
0
0
.0
0
0.4
0.6
0.8
0.2
0.4
0.6
0.8
µm
µm
nm
Fig. 1. The surface morphology of a nanocomposite layer pre-
pared using CdS.
G.S. Svechnikov et al.: Composite film structures containg ZnS, CdS nanoparticles ...
159SQO, 7(2), 2004
The photoluminescence spectra of the composite poly-
meric structures including ZnS and CdS particles are sub-
mitted in Figs 2 and 3. The wide band in the range of 400 to
700 nm peaking at 590 nm was observed in spectra of the
composite structure based on ZnS grown on the substrate
at temperatures of 100�120°Ñ (Fig. 2, curve 1). The lumi-
nescence band contains �shoulders� at 650, 520 and 450 nm.
It testifies that this band is complex and contains, at least,
three bands in red, green and dark blue areas of the spec-
trum. Such spectral structure causes yellow colour of lumi-
nescence. The decrease of the substrate temperature re-
sults in the change of a luminescence colour from yellow to
blue. Such change of a luminescence colour is caused by
the change of the contribution of various emitting bands
into common intensity. The contribution of more high-en-
ergy emitting bands is increased when the substrate tem-
perature is decreased from 120 down to 50°Ñ. At the substrate
temperature 50°Ñ, the luminescence peak is located at
500 nm. In this case, the structure has the blue colour of
luminescence, because the dark blue emission band peak-
ing at 450 nm gives a main contribution to luminescence.
The half-width of the photoluminescence band is de-
creased.
The effect of �blue� displacement is expressed even
more sharply (Fig. 3) for composite layers based on CdS. In
this case, the luminescent spectrum of the layer deposited
on the substrate at 100°Ñ has a wide band with a maxi-
mum at 500 nm and two less intense bands in orange
(580 nm) and red (650 nm) spectral regions. It is neces-
sary to note that green emission in monocrystals and
polycrystalline CdS films, as a rule is observed only at
low temperature (~ 77 Ê) [12]. The decrease of a substrate
temperature at the precipitation of polymeric composite
layer results in sharp reduction of intensity of long-wave
bands and growth of the short-wave emission intensity.
Simultaneously, the displacement of a short-wave emis-
sion peak from 500 nm down to 450 nm is observed. In
this case, the halfwidth of the photoluminescence band is
nearly halved.
The presence of the green band in the photolumines-
cence spectrum of layers based on CdS even at the room
temperature, apparently, due to using high-energy excita-
tion (N2 - laser, λ = 337 nm) and presence of a sufficient
set of grains with a rather perfect crystal structure. The
50 nm shift of the green emission band into the short-
wave spectral region correlates with an increase of the
contribution of very small grains (~5 nm) into the total
luminescent intensity and can be explained by the pres-
ence of the quantum size effect [4] in CdS nanocrystals.
Apparently, it testifies that the composite layers formed
at low temperatures contain CdS (ZnS) crystals with very
small sizes, which provide a more short-wave emission in
comparison with monocrystals and polycrystalline films.
4. Conclusions
Thus, the new composite structures containing ZnS and
CdS nanoparticles were prepared. These structures pos-
sess bright blue luminescence.
400 450 500 550 600 650 700 750
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
In
te
n
si
ty
,
a
rb
.
u
n
it
s
1 2 3
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
In
te
n
si
ty
,
a
rb
.
u
n
it
s
400 450 500 550 600 650 700 750
1 2 3
Fig. 2. The photoluminescence spectra of nanocomposite layers
based on ZnS and obtained at various substrate temperatures: 1 � 50,
2 � 90, and 3 � 120°Ñ.
Fig. 3. The photoluminescence spectra of nanocomposite layers
based on CdS and obtained at various substrate temperatures: 1 � 40,
2 � 60, and 3 � 100°Ñ.
Wavelength, nm Wavelength, nm
160
SQO, 7(2), 2004
G.S. Svechnikov et al.: Composite film structures containg ZnS, CdS nanoparticles ...
The change of a luminescence colour from yellow to
green and dark blue is achieved by the change of a substrate
temperature at the constant component composition. To
shift the luminescence into the short-wave region, it is not
necessary to increase, as usual, but decrease the substrate
temperature from 120 down to 40�60°Ñ. This execution
satisfies to more nonequilibrium rate of a crystals growth
and reduces their sizes.
This method for preparation of light-emitting struc-
tures is very cheap because allows to use glasses of simple
marks and flexible substrates.
References
1. M.A. Rid, Quantum dots // V mire nauki, (2,3), pp. 130-136
(1993).
2. R.N. Bhargava, D. Gallagher, X. Hong, A. Nurmikko, Opti-
cal properties of manganese-doped nanocrystals of ZnS //
Phys. Rev. Lett., 72(3), pp. 416-419 (1994).
3. M. Wang, L. Sun, X. Fu, C. Liao, C. Yan, Synthesis and
optical properties of ZnS:Cu(II) nanoparticles // Solid State
Communications, 115, pp. 493-496 (2000).
4. L.V. Colvin, M.C. Schlamp and A.P. Alivisatos, Light-emit-
ting diodes made from cadmium selenide nanocrystals and
a semiconducting polymer // Letters to nature, 370, pp. 81-
83 (1994).
5. D. Matsuura, Y. Kanemitsu, Photoluminescence dynamics of
CdS nanocrystals fabricated by sequential ion implantation //
Jpn. J. Appl. Phys., 40, pp.2092-2094 (2001).
6. L.F. Zharovsky, L.V. Zavyalova, G. S. Svechnikov, Metal-
chalcogenides films prepared from Chelate metal-organic com-
pound // Thin Solid Films, 128(3,4), pp.241-249 (1985).
7. J. Stary, The solvent extraction of metal chelates, Pergamon
Press, p. 392 (1964).
8. L.V. Zavyalova, A.I. Beletski and G. S. Svechnikov, ZnS:Mn
films prepared by MOCVD method // Semicond. Sci. Technol.,
14, pp. 446-449(1999).
9. V.M. Birko, Ditiocarbamats, �Nauka�, Moscow, p. 342 (1984)
10. L. V. Zavyalova and G. S. Svechnikov // Displays, 18, pð.73-78
(1997).
11. D. M. Frigo, O. Khan, P. O. Brien // J. Cryst. Growth, 96, p. 989
(1989).
12. S. Jursenas, V. Stepankevicius, M. Strumskis, A. Zukauskas //
Semicond. Sci. Technol., 10, pp. 302-309 (1995).
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