Structural, optical, and electrical properties of ZnO: al prepared by CVD
In this paper we will prepared thin films from transparent conductive oxide(TCO) ZnO pure, and doped for various concentration of aluminum (4,8%) using technique chemical vapor deposition (CVD) at different substrates temperatures (400, 450, 500 °C) on glass substrates. The films were characterized...
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| Опубліковано в: : | Физическая инженерия поверхности |
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| Дата: | 2011 |
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Науковий фізико-технологічний центр МОН та НАН України
2011
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Structural, optical, and electrical properties of ZnO: al prepared by CVD / A.D. Pogrebnyak, N.Y. Jamil, A.K.M. Muhammed // Физическая инженерия поверхности. — 2011. — Т. 9, № 3. — С. 244–249. — Бібліогр.: 5 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860065199456780288 |
|---|---|
| author | Pogrebnyak, A.D. Jamil, N.Y. Muhammed, A.K.M. |
| author_facet | Pogrebnyak, A.D. Jamil, N.Y. Muhammed, A.K.M. |
| citation_txt | Structural, optical, and electrical properties of ZnO: al prepared by CVD / A.D. Pogrebnyak, N.Y. Jamil, A.K.M. Muhammed // Физическая инженерия поверхности. — 2011. — Т. 9, № 3. — С. 244–249. — Бібліогр.: 5 назв. — англ. |
| collection | DSpace DC |
| container_title | Физическая инженерия поверхности |
| description | In this paper we will prepared thin films from transparent conductive oxide(TCO) ZnO pure, and doped for various concentration of aluminum (4,8%) using technique chemical vapor deposition (CVD) at different substrates temperatures (400, 450, 500 °C) on glass substrates. The films were characterized by X-ray diffraction and UV spectrometer, pure ZnO films and (ZnO: Al) shows, a polycrystalline structure of the hexagonal wurtzite type, the diagnostics show preferred peaks for the growth of the crystal grains in the directions (002). The optical measurements have shown that the absorption edge is shifted towards the shortwave lengths which mean that the energy gap increases with the increase of aluminum concentration that we obtained Eg = 3.6 in case of 8% doping Al, and then we noticed the transmittance increases with increasing the substrate temperature and doping percentage with aluminum and the highest value was observed at 500 °C and (8%) doping. The electric conductivity of ZnO films doped with aluminum increases with the percentage of doping until the doping percentage of (4%), then starts to decrease with the increase in doping percentages at substrate temperatures (450 °C and 500 °C).
В работе тонкие пленки получены из прозрачного проводящего оксида (ППO), чистого ZnO, легированного алюминием Al (4,8%) различной концентрации. Пленки формировались методом химического осаждения из газовой фазы (CVD) на стеклянные подложки при различных температурах (400 °C, 450 °C, 500 °C). Пленки чистого ZnO и (ZnO: Al) исследовались с помощью метода рентгеновской дифракции с использованием УФ спектрометра. Исследования показали гексагональную поликристаллическую структуру типа вюрцита. Диагностика показала преимущественные пики роста кристаллических зерен в направлениях (002). Оптическими измерениями показано, что пик поглощения смещается в сторону коротких волн, что указывает на увеличение энергетического зазора с повышением концентрации алюминия в ZnO. Отметим также, что коэффициент пропускания увеличивался с повышением температуры подложки и процентного соотношения легированного алюминия. Максимальное значение наблюдалось при 500 °C и процентном соотношении легированного алюминия (8%). Электропроводность пленок ZnO, легированных алюминием, возрастала с увеличением процентного соотношения легируемого материала до (4%), а затем начинала уменьшаться, не смотря на увеличение процентного соотношения легированного материала при температуре подложки (400 °C и 500 °C).
У роботі тонкі плівки виготовлені з прозорого провідникового оксиду (ППO) чистого ZnO, легованого алюмінієм (4,8 %) різної концентрації. Нанесення здійснювалося методом хімічного осадження з газової фази (CVD) на скляні підкладки при різних температурах (400 °C, 450 °C, 500 °C). Плівки чистого ZnO і (ZnO: Al) досліджувалися за допомогою методу рентгенівської дифракції з використанням УФ спектрометра. Дослідженнями встановлено гексагональну полікристалічну структуру типу вюрциту. Діагностика показала переважні піки росту кристалічних зерен у напрямках (002). Оптичними вимірюваннями встановлено, що пік поглинання зміщується у бік коротких хвиль, яка вказує на збільшення енергетичного зазору із підвищенням концентрації алюмінію в ZnO. Зазначимо також, що коефіцієнт пропускання підвищувався зі зростанням температури підкладки і процентного співвідношення легованого алюмінію. Максимальне значення спостерігалося при 500 °C та відсотковому співвідношенні легованого алюмінію (8%). Електропровідність плівок ZnO, легованих алюмінієм, зростала зі збільшенням процентного співвідношення легованого матеріалу до (4%), а потім спостерігається зменшення, не зважаючи на зростання процентного співвідношення легованого матеріалу при температурі підкладки (450 °C і 500 °C).
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244
УДК 621.715.539.376
STRUCTURAL, OPTICAL, AND ELECTRICAL PROPERTIES OF ZnO:
Al PREPARED BY CVD
A.D. Pogrebnyak1, N.Y. Jamil2, A.K.M. Muhammed1
1Sumy State University, Ukraine
2University of Mosul, Iraq
Received 25.09.2011
In this paper we will prepared thin films from transparent conductive oxide(TCO) ZnO pure, and do-
ped for various concentration of aluminum (4,8%) using technique chemical vapor deposition (CVD)
at different substrates temperatures (400, 450, 500 °C) on glass substrates. The films were characterized
by X-ray diffraction and UV spectrometer, pure ZnO films and (ZnO: Al) shows, a polycrystalline
structure of the hexagonal wurtzite type, the diagnostics show preferred peaks for the growth of the
crystal grains in the directions (002). The optical measurements have shown that the absorption edge
is shifted towards the shortwave lengths which mean that the energy gap increases with the increase
of aluminum concentration that we obtained Eg = 3.6 in case of 8% doping Al, and then we noticed
the transmittance increases with increasing the substrate temperature and doping percentage with
aluminum and the highest value was observed at 500 °C and (8%) doping. The electric conductivity
of ZnO films doped with aluminum increases with the percentage of doping until the doping percentage
of (4%), then starts to decrease with the increase in doping percentages at substrate temperatures
(450 °C and 500 °C).
Keywords: thin film, chemical vaporous deposition, ZnO, doping, energy gap.
В работе тонкие пленки получены из прозрачного проводящего оксида (ППO), чистого ZnO,
легированного алюминием Al (4,8%) различной концентрации. Пленки формировались методом
химического осаждения из газовой фазы (CVD) на стеклянные подложки при различных тем-
пературах (400 °C, 450 °C, 500 °C). Пленки чистого ZnO и (ZnO: Al) исследовались с помощью
метода рентгеновской дифракции с использованием УФ спектрометра. Исследования показали
гексагональную поликристаллическую структуру типа вюрцита. Диагностика показала преиму-
щественные пики роста кристаллических зерен в направлениях (002). Оптическими изме-
рениями показано, что пик поглощения смещается в сторону коротких волн, что указывает на
увеличение энергетического зазора с повышением концентрации алюминия в ZnO. Отметим
также, что коэффициент пропускания увеличивался с повышением температуры подложки и
процентного соотношения легированного алюминия. Максимальное значение наблюдалось
при 500 °C и процентном соотношении легированного алюминия (8%). Электропроводность
пленок ZnO, легированных алюминием, возрастала с увеличением процентного соотношения
легируемого материала до (4%), а затем начинала уменьшаться, не смотря на увеличение проц-
ентного соотношения легированного материала при температуре подложки (400 °C и 500 °C).
Ключевые слова: тонкие пленки, химическое парообразное осаждение, ZnO, импульсное
лазерное напыления.
У роботі тонкі плівки виготовлені з прозорого провідникового оксиду (ППO) чистого ZnO, ле-
гованого алюмінієм (4,8 %) різної концентрації. Нанесення здійснювалося методом хімічного
осадження з газової фази (CVD) на скляні підкладки при різних температурах (400 °C, 450 °C,
500 °C). Плівки чистого ZnO і (ZnO: Al) досліджувалися за допомогою методу рентгенівської
дифракції з використанням УФ спектрометра. Дослідженнями встановлено гексагональну
полікристалічну структуру типу вюрциту. Діагностика показала переважні піки росту
кристалічних зерен у напрямках (002). Оптичними вимірюваннями встановлено, що пік по-
глинання зміщується у бік коротких хвиль, яка вказує на збільшення енергетичного зазору із
підвищенням концентрації алюмінію в ZnO. Зазначимо також, що коефіцієнт пропускання
підвищувався зі зростанням температури підкладки і процентного співвідношення легованого
алюмінію. Максимальне значення спостерігалося при 500 °C та відсотковому співвідношенні
легованого алюмінію (8%). Електропровідність плівок ZnO, легованих алюмінієм, зростала зі
збільшенням процентного співвідношення легованого матеріалу до (4%), а потім спостерігаєть-
A.D. Pogrebnyak, N.Y. Jamil, A.K.M. Muhammed, 2011
245ФІП ФИП PSE, 2011, т. 9, № 3, vol. 9, No. 3
INTRODUCTION
In the resent years, ZnO have received conside-
rable attention due to its application in electrical,
optical, mechanical and scientific research’s as
well as industry. Zinc Oxide is an II-VI wide band
gap semiconductor with a large band gap of about
3.3 eV is one of the most potential materials for
being used as a TCO because of it’s good elect-
rical and optical properties, abundance in nature,
absence of toxicity [1, 2] and the ability to deposit
these films at relatively low temperatures [3].
The oxygen vacancies and/or zinc interstitials
correspond to the n-type conductivity of the ZnO
films. The resistivity of these films can be further
lowered by doping them with group III elements
like B, Al, Ga or In. Among all these elements,
Al is considered to be a good dopant for opto-
electronic applications like solar cells due to the
high transmittance that Al-doped ZnO films
exhibit. ZnO: Al is fabricated by RF magnetron
sputtering [4, 5], sol-gel process [3], pulsed laser
deposition [5], spray pyrolysis [6] and chemical
vapor deposition [7], etc. Among them, chemical
vapor deposition that used in this paper, the pro-
cess of deposition and producing homogeneous
films is not a simple process but requires a num-
ber of tests including the selection of the pre-
cursor material, the temperature of substrates, the
evaporation temperature and the flow rate of the
carrier gasses in addition to the location of the
sample in the deposition chamber. All these fac-
tors have a direct effect on the type of the requi-
red prepared film that and on its physical pro-
perties. In this study we observed a number of
observations concerning the films. In some
instance the films did not grow over the subst-
rates or they only partly covered them. In other
instances we observed that the films were formed
as stripes. These cases took place at temperatures
less than 450 °C. While at this temperature and
above, we found that the films status was en-
hanced significantly concerning the rate of
growth and homogeneity while the optimal
temperature degree in this study was found to be
500 °C as the optical, and electrical properties
of the films.
EXPERIMENTAL PROCEDURE
In order to prepare pure ZnO films using chemi-
cal vapors deposition (CVD) techniques on glass
and substrates the deposition material used was
pure zinc acetate hydrous Zn(CH3COO)2⋅2H2O
with 98% purity. After preparing the substrates,
they were placed and adjusted in the deposition
unit while the temperature degrees were varied
between (400 – 500 °C) in order to ensure opti-
mum film properties. The pressurized air flow
was also adjusted to the best flow rate which was
found to be 2 L/min to produce the best samples
as. The rate of airflow is related to the uniformity
of the deposited film and it must be adjusted to
prevent the formation of colored strips on the
glass substrates that can interfere with visional
and microscopic inspection. Various temperature
degrees were tested when heating the deposition
material and it was found that the temperature
of (340 °C – 350 °C) is the appropriate tem-
perature degree range. Deposition time was kept
constant at (20 min.) for the both the pure and
doped samples in order to determine the com-
bination of optimal duration with temperature
degree that produces the best results of zinc oxide
deposition and the samples were left afterwards
to cool. The first choice of doping material was
to use chloride aluminum hydrous as a doping
material but it was not possible to produce a
doped film in any of the varied deposition con-
ditions. The reasons were attributed to the weak
or lack reaction ability between the Zn and hyd-
rous aluminum. This led us to seek a different
material which was aluminum nitrate hydrous
with a purity of (98.5%). After using this com-
pound, aluminum doped ZnO films were suc-
cessfully produced with good homogeneity. The
various weight percentages of this used material
were between (4,8%) that were added to the
weight percentages of zinc acetate. The following
equations show how ZnO is produced
Zn(CH3COO)2⋅2H2O → ZnO + CO2 +
+ CH3 + steam. (1)
The following equation used to get the lattice
constant [3],
ся зменшення, не зважаючи на зростання процентного співвідношення легованого матеріалу
при температурі підкладки (450 °C і 500 °C).
Ключові слова: тонкі плівки, хімічне пароподібне осадження, ZnO, імпульсне лазерне на-
пилення.
A.D. POGREBNYAK, N.Y. JAMIL, A.K.M. MUHAMMED
246
2 2 2
2 2 2
1 4
3hkl
h hk k L
d a C
+ += ⋅ + , (2)
where a, C is lattice constant, h, k, L is Miller
indices.
The crystalline structure was analyzed by X-
ray diffractometer (DRОТ-20 v Сu-kα) in the ran-
ge 2θ of 30 – 80, the surface morphology of the
films was analyzed using scanning electron
microscope model (REM-106) before and after
annealing. The optical transmittance was mea-
sured using a ENGLAND (1000 SERIES a”
CECIL 1021) spectrophotometer in the wave-
length range from 300 to 1000 nm.
RESULTS AND DISCUSSION
STRUCTURAL PROPERTIES
X-ray diffraction studies of the structure of the
material were carried out on an automated
DRON-4-07 (“Bourevestnik”, www.bourevest-
nik.spb.ru). Automation system using a DRON-
4-07 is based on a microprocessor controller that
provides control of the goniometer GUR-9 and
data transmission in digital form on a PC.
Fig. 1, table 1 displays the XRD spectrum of
ZnO films. Three lines (100) at 2θ = 31.76°,
(002) at 2θ = 34.47°, (101) at 2θ = 36.24° are
pointed, they will be considered for structural
characterization of ZnO. We measured the XRD
spectra for ZnO: Al with different Al ratio
(weight) from 4% to 8% and found the following
results, The films exhibit a dominant peak
corresponding to the (002) plane of ZnO, and
other peaks corresponding to (100), (101), and
indicating the polycrystalline nature of the films.
It is seen from the figure that the relative intensity
of the (002) peak decrease with increasing Al
dopant concentration. The decrease in peak
intensity indicates an improvement in the
crystalline of the films. Besides, a slight shift
was observed in the peaks in the direction of the
lesser angles which may be attributed to the small
increase in the bond. These result were confirmed
with those obtained from the Joint committee of
powder diffraction standards JCPDS for the ZnO.
Table 1
Lattice parameter of ZnO
No 2θ, Degree h k L dhkl, D a, D c, D
Result standard
dhkl, D (a, c), D
ZnO
a = 3.249
c = 5.206
31.72 1 0 0 2.816 2.814
34.76 0 0 2 2.56 2.603
36.6 1 0 1 2.456 2.475
3.24 5.17
Fig. 1. X-ray diffraction of ZnO, a) – pure, b0 – 4% doping,
c) – 8% doping.
a)
b)
c)
ФІП ФИП PSE, 2011, т. 9, № 3, vol. 9, No. 3
STRUCTURAL, OPTICAL, AND ELECTRICAL PROPERTIES OF ZnO: Al PREPARED BY CVD
247ФІП ФИП PSE, 2011, т. 9, № 3, vol. 9, No. 3
SURFACE MORPHOLOGY
Microscope test process has been done after
finishing from depositing ZnO thin film on glass
substrate by (CVD).
It can be easily seen that the grains are tightly
packed. And we can see that the smoothly surface
was obtained in case of Al doping in 4% as shown
in fig. 2.
OPTICAL PROPERTIES
Fig. 3 show the absorption spectra as a function
of the wavelength of the pure ZnO films and the
ZnO films doped with (4,8%) aluminum. From
these figures, we can see the transmission decre-
ased with decrease wavelength, also we can see
two regions are obvious: The first was the region
wave length energy larger than the energy gap
(Eg > 3 eV) which equals to (λ < 400 nm) as du-
ring this region, the absorption increase sharply
therefore shows that the ZnO: Al can be used as
UV protection films
The second region lies within the wavelengths
range of (400 < λ < 1000 nm) in which the energy
of the incident photon is low and the (ZnO: Al)
film is transparent to this range and the absorp-
tion is lowest. We can see from the fig. 4 that the
increase in the percentage of aluminum added
to the ZnO leads to the shift in the absorption to-
wards the short wavelengths, a shift that is termed
(Burstein-Moss) shift. This type of shift leads to
an increase in the optical energy gap, also we
can see the decrease of wave length, as its value
very high at the wave length which is located
within optical spectrum and infra-red radiation,
which indicates that these films have large energy
gap to allow most of the visible light to pass as
shown in figure, also the results show that the
transmittance is higher than 80% in all thin films.
The optical energy gap (Eopt) is defined as the
lowest energy required for the electron to travel
from the peak of the coordinate band to the peak
of conductivity band and can be calculated di-
rectly using the electron traveling formula as fol-
lows:
α(hv) = A(hv – Eopt)
1/2, (3)
and can be rewritten as follows
(αhv)2 = A2(hv – Eopt), (4)
and when (αhv)2 = 0, then Eopt = hv.
The relationship between (αhv)2 and (hv) can
be plotted as a curve and the extended part of
the curve intersects with the photon energy axis
at (hv)2 = 0 and from it we determine the energy
gap of direct allowed traveling as shown in
fig. 4, as shows the energy gaps for pure ZnO
and doped with a (4,8%) aluminum.
An obvious increase is observed for the values
of the energy gap with the increase in the
concentration of aluminum and is in accord with
previous studies (4, 5) within various preparation
techniques, this increase is explained by the
preposition that the ZnO: Al films are semicon-
ductors in which the Fermi level lies in the con-
ducive band which means that the levels at the
bottom of the conductivity band are occupied by
electrons and the shielding of electronic traveling
to these levels is termed the Burstein-Moss effect.
For these films, Eopt is determined from the inter-
Fig. 2. Seem image of thin film ZnO, a) – pure, b) – 4 %
doping Al, c) – 8 % doping.
Fig. 3. Transmittance spectra as a function of wave length
for ZnO samples deposited at various temperatures (400,
450, 500 °C).
A.D. POGREBNYAK, N.Y. JAMIL, A.K.M. MUHAMMED
248
section of the straight lines of the curve with
the energy axis at (hv), and Eopt was found to be
(3.25, 3.4, 3.6) eV.
ELECTRICAL PROPERTIES
Fig. 5 shows the change in the electric conduc-
tivity of ZnO un doped and doping with alumi-
num at (4,8%). The effect of doping on the elect-
ric conductivity was determined at various do-
ping percentages and it was shown in figure that
doping had a significant effect of the electric
conductivity of ZnO doped with aluminum.
Fig. 5 shows the change in the electric con-
ductivity of pure ZnO films doped with alumi-
num at (4,8%) at substrate temperatures of (400,
450, and 500 °C). It is shown that the electric
conductivity increases with the increase in the
temperature of the substrate and reaches it hig-
hest level at a substrate temperature of 500 °C.
The reason attributed to this increase in conduc-
tivity with the increase in the substrate tempe-
rature is the improvement of crystal structure and
then increase in the crystal grains which leads to
a decrease in the scattering of the charge carriers
at the edges of the grains and in turn increases
the mobility of the carriers and conductivity.
And then the effect of doping on the electric
conductivity was determined at various doping
percentages and it was shown in fig. 5 that do-
ping had a significant effect of the electric con-
ductivity of ZnO doped with aluminum. At
(T = 400 °C) the electric conductivity is low in
general when compared with the substrate
temperatures of (450, and 500 °C). At (450 and
500 °C) the electric conductivity increased when
the doping with aluminum increased until 5 %
were after that percentage of doping the electric
conductivity decreased. The increase in electric
conductivity of films doped with an average per-
centage of aluminum is due to the atoms of triple
metals like aluminum that interacts with him film
in various was and the aluminum atoms com-
pensate the Zn locations in the Alzn lattice acting
as donors as shown in the following formula:
Al3 → Al2 + e, (5)
Al2+ occupies the locations in the ZnO lattice and
(e) the free electrons that participate in electric
conductivity.
CONCLUSION
The most important conclusions reached by the
study are as follows: from the X-ray diffraction
we found, the effects of different aluminum con-
centrations on the structural properties, electrical
resistivity and optical transparency of the films
were studied, the films exhibit a dominant peak
corresponding to the (002) plane of ZnO, and
other peaks corresponding to (100), (101), and
indicating the polycrystalline nature of the films.
It is seen from the figure that the relative intensity
of the (002) peak decrease with increasing Al
dopant concentration. The decrease in peak in-
tensity indicates an improvement in the crys-
talline of the films. The seam morphology shows
the grains are tightly packed, and we can see that
the smoothly surface was obtained in case of Al
doping in 4%, from the optical properties we can
see the transmission increases with the increase
in concentration of doping aluminum, the highest
transmission is observed at (8%) doping, also
the results show that the transmittance is higher
than 80% in all thin films. The value of the band
gap is enhanced from 3.25 eV (un doped ZnO
thin film) to 3.65 in case of doping with 8%.
The increase in the band gap can be explained
Fig. 4. Measurement of energy band gap for ZnO deposi-
ted at various temperatures (400, 450, 500 °C).
Fig. 5. Electric conductivity of ZnO un doped, and doping
with (4,8%) for various substrate temperature (400, 450,
500 °C).
ФІП ФИП PSE, 2011, т. 9, № 3, vol. 9, No. 3
STRUCTURAL, OPTICAL, AND ELECTRICAL PROPERTIES OF ZnO: Al PREPARED BY CVD
249ФІП ФИП PSE, 2011, т. 9, № 3, vol. 9, No. 3
by the Burstein-Moss effect. The ZnO films show
good electric conductivity at (450 and 500 °C)
and was found to be 9.740741 (Ω cm)–1 and
14.34615 (Ω cm)–1, and then the electric condu-
ctivity of The ZnO films doped with aluminum
increases with the increase in temperature and
doping, the highest was 19.34615 (Ω cm)–1 at
500 °C and 4% doping, then starts to decrease
with the increase in doping percentages at the
temperatures (450 °C and 500 °C).
REFERENCES
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LITERATURA
1. Joseph B., Manoj P.K., Vajdyan V.K. Studies on
preparation and characterization of indium doped
oxide films by chemical spray deposition//Bull.
Mater. Science. – 2005. – Vol. 28, No. 5. –
P. 487-493.
2. Yusta F.J., Hitsman M.L., Shamlian S.H. CVD
preparation and characterization on thin dioxide
films for electrochemical application//J. Ma-
terials Chemistry. – 1997. – Vol. 7, No. 8. –
P. 1421-1427.
3. De Merchant J., Cocivera M. Preparation and
doping of zinc oxide using spray pyrolysis//Che-
mistry of Materials. – 1995. – Vol. 7, No. 9. –
P. 1742-1749.
4. Sushea M., Christoulakis S., Moschovisk K., et.
al. Nanostruktured ZnO and ZAO transparen thin
filma by sputtering-surface characterization//
Rev. Advanced Materials Science. – 2005. –
Vol. 10. – P. 335-340.
5. Gorelik C.S., Rastorguev L.N., Skakov Ju.A.
Rentgenograficheskij i jelektronnoopticheskij
analiz. Prilozhenie. – M.: Metallurgija, 1970. –
109 s.
A.D. POGREBNYAK, N.Y. JAMIL, A.K.M. MUHAMMED
|
| id | nasplib_isofts_kiev_ua-123456789-76893 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1999-8074 |
| language | English |
| last_indexed | 2025-12-07T17:06:43Z |
| publishDate | 2011 |
| publisher | Науковий фізико-технологічний центр МОН та НАН України |
| record_format | dspace |
| spelling | Pogrebnyak, A.D. Jamil, N.Y. Muhammed, A.K.M. 2015-02-13T06:34:51Z 2015-02-13T06:34:51Z 2011 Structural, optical, and electrical properties of ZnO: al prepared by CVD / A.D. Pogrebnyak, N.Y. Jamil, A.K.M. Muhammed // Физическая инженерия поверхности. — 2011. — Т. 9, № 3. — С. 244–249. — Бібліогр.: 5 назв. — англ. 1999-8074 https://nasplib.isofts.kiev.ua/handle/123456789/76893 621.715.539.376 In this paper we will prepared thin films from transparent conductive oxide(TCO) ZnO pure, and doped for various concentration of aluminum (4,8%) using technique chemical vapor deposition (CVD) at different substrates temperatures (400, 450, 500 °C) on glass substrates. The films were characterized by X-ray diffraction and UV spectrometer, pure ZnO films and (ZnO: Al) shows, a polycrystalline structure of the hexagonal wurtzite type, the diagnostics show preferred peaks for the growth of the crystal grains in the directions (002). The optical measurements have shown that the absorption edge is shifted towards the shortwave lengths which mean that the energy gap increases with the increase of aluminum concentration that we obtained Eg = 3.6 in case of 8% doping Al, and then we noticed the transmittance increases with increasing the substrate temperature and doping percentage with aluminum and the highest value was observed at 500 °C and (8%) doping. The electric conductivity of ZnO films doped with aluminum increases with the percentage of doping until the doping percentage of (4%), then starts to decrease with the increase in doping percentages at substrate temperatures (450 °C and 500 °C). В работе тонкие пленки получены из прозрачного проводящего оксида (ППO), чистого ZnO, легированного алюминием Al (4,8%) различной концентрации. Пленки формировались методом химического осаждения из газовой фазы (CVD) на стеклянные подложки при различных температурах (400 °C, 450 °C, 500 °C). Пленки чистого ZnO и (ZnO: Al) исследовались с помощью метода рентгеновской дифракции с использованием УФ спектрометра. Исследования показали гексагональную поликристаллическую структуру типа вюрцита. Диагностика показала преимущественные пики роста кристаллических зерен в направлениях (002). Оптическими измерениями показано, что пик поглощения смещается в сторону коротких волн, что указывает на увеличение энергетического зазора с повышением концентрации алюминия в ZnO. Отметим также, что коэффициент пропускания увеличивался с повышением температуры подложки и процентного соотношения легированного алюминия. Максимальное значение наблюдалось при 500 °C и процентном соотношении легированного алюминия (8%). Электропроводность пленок ZnO, легированных алюминием, возрастала с увеличением процентного соотношения легируемого материала до (4%), а затем начинала уменьшаться, не смотря на увеличение процентного соотношения легированного материала при температуре подложки (400 °C и 500 °C). У роботі тонкі плівки виготовлені з прозорого провідникового оксиду (ППO) чистого ZnO, легованого алюмінієм (4,8 %) різної концентрації. Нанесення здійснювалося методом хімічного осадження з газової фази (CVD) на скляні підкладки при різних температурах (400 °C, 450 °C, 500 °C). Плівки чистого ZnO і (ZnO: Al) досліджувалися за допомогою методу рентгенівської дифракції з використанням УФ спектрометра. Дослідженнями встановлено гексагональну полікристалічну структуру типу вюрциту. Діагностика показала переважні піки росту кристалічних зерен у напрямках (002). Оптичними вимірюваннями встановлено, що пік поглинання зміщується у бік коротких хвиль, яка вказує на збільшення енергетичного зазору із підвищенням концентрації алюмінію в ZnO. Зазначимо також, що коефіцієнт пропускання підвищувався зі зростанням температури підкладки і процентного співвідношення легованого алюмінію. Максимальне значення спостерігалося при 500 °C та відсотковому співвідношенні легованого алюмінію (8%). Електропровідність плівок ZnO, легованих алюмінієм, зростала зі збільшенням процентного співвідношення легованого матеріалу до (4%), а потім спостерігається зменшення, не зважаючи на зростання процентного співвідношення легованого матеріалу при температурі підкладки (450 °C і 500 °C). en Науковий фізико-технологічний центр МОН та НАН України Физическая инженерия поверхности Structural, optical, and electrical properties of ZnO: al prepared by CVD Article published earlier |
| spellingShingle | Structural, optical, and electrical properties of ZnO: al prepared by CVD Pogrebnyak, A.D. Jamil, N.Y. Muhammed, A.K.M. |
| title | Structural, optical, and electrical properties of ZnO: al prepared by CVD |
| title_full | Structural, optical, and electrical properties of ZnO: al prepared by CVD |
| title_fullStr | Structural, optical, and electrical properties of ZnO: al prepared by CVD |
| title_full_unstemmed | Structural, optical, and electrical properties of ZnO: al prepared by CVD |
| title_short | Structural, optical, and electrical properties of ZnO: al prepared by CVD |
| title_sort | structural, optical, and electrical properties of zno: al prepared by cvd |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/76893 |
| work_keys_str_mv | AT pogrebnyakad structuralopticalandelectricalpropertiesofznoalpreparedbycvd AT jamilny structuralopticalandelectricalpropertiesofznoalpreparedbycvd AT muhammedakm structuralopticalandelectricalpropertiesofznoalpreparedbycvd |