Zinc Oxide thin films doped with Ag have been synthesized by CVD technique. By increasing the dopant from 0 to 10 % Ag in ZnO thin films were found to lead to pronounced changes in their morphology. From optical properties the band gap energy of pure ZnO thin film was 3.25 eV, with the increasing of Ag doping from 1 to 10% it is not affected. X-ray diffraction has shown that the maximum intensity peak corresponds to the (101) predominant orientation for ZnO and ZnO:Ag. SEM images show that more crystalline behavior by increasing the doping. EDXA analysis showed that the structure of ZnO film contains Zn and O elements and Ag, Cu, Si for doping at 10 % Ag

Jamil, N.Y.

Muhammed, A.M.

Najim, S.A.

Rogoz, V.M.

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  
NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 3 No 2, 02NEA09(3pp) (2014) 
 
 
2304-1862/2014/3(2)02NEA09(3) 02NEA09-1  2014 Sumy State University 
Preparation, Structural and Optical Characterization of ZnO / Ag Thin Film by CVD 
 
N.Y. Jamil1, S.A. Najim1, A.M. Muhammed2, *, V.M. Rogoz2 
 
1 Physics DeP., College of Science, Mosul Univ., Mosul, Iraq 
2 Sumy State University, 2, Rimsky-Korsakov Str., 40007 Sumy, Ukraine 
 
(Received 15 July 2014; published online 29 August 2014) 
 
Zinc Oxide thin films doped with Ag have been synthesized by CVD technique. By increasing the 
dopant from 0 to 10 % Ag in ZnO thin films were found to lead to pronounced changes in their morphology. 
From optical properties the band gap energy of pure ZnO thin film was 3.25 eV, with the increasing of Ag 
doping from 1 to 10 % it is not affected. X-ray diffraction has shown that the maximum intensity peak 
corresponds to the (101) predominant orientation for ZnO and ZnO:Ag. SEM images show that more 
crystalline behavior by increasing the doping. EDXA analysis showed that the structure of ZnO film 
contains Zn and O elements and Ag, Cu, Si for doping at 10 % Ag. 
 
Keywords: CVD, X-ray Diffraction, SEM. 
 
 PACS number: 62.20.Qp 
                                                          
*kareem19592003@yahoo.co.uk 
 
 
1. INTRODUCTION 
 
Transparent conducting n-type semiconductor zinc 
oxide (ZnO) films have been extensively studied in 
recent year because they exhibit wide band gap [1, 2], 
optical transmission, electrical conduction and exciton 
binding energy of 60 meV [2] at room temperature. 
This exciton binding energy is much larger than the 
room temperature thermal energy (26 meV), suggesting 
that the electron-hole pairs are stable even at room 
temperature. It has crystalline structure of the 
wurtzite type and with lattice constants a = 3.24 ?, c = 
5.19 ? [3]. ZnO thin film is a promising material in the 
applications of UV light devices, light emitting diodes 
(LEDs) and laser systems [4], and is used in 
antireflection coatings, transparent electrodes in solar 
cells, piezoelectric devices, gas sensors [5], etc. Several 
techniques were used to prepare ZnO thin films 
namely: thermal evaporation [6], spray pyrolysis [5-6], 
RF/DC magnetron sputtering [7], chemical vapour 
deposition (CVD) methods [5,8], Molecular beam 
epitaxy [9], pulsed-laser deposition (PLD) [10], 
chemical bath deposition technique [11], hydrothermal 
method [12] and sol–gel [13]. Doping is done to control 
the ZnO physical properties. Usually, n-type doping is 
obtained by Al, Ag, Ga or In. On the other hand, p-type 
doping is not easily obtained. However, it is difficult to 
achieve visible light absorption on a single ZnO 
material. The silver Ag have been mostly extensively 
investigated as the important candidate for wide band 
gap material to absorb light. Ag offer high performance 
absorption in visible light without any highly toxic 
elements. Many different methods have been used to 
prepare Ag–ZnO thin films , RF magnetron sputtering 
method [8], CVD [5], and so on. However, there are few 
report on the preparation of Ag–ZnO film on the glass 
substrate by CVD. It was an important method to 
synthesize films. The method is cost-effective, simple 
and can be carried out under low temperature. In this 
paper, the simple CVD method was used to obtain the 
ZnO/Ag thin film on the glass substrate. Effects of Ag 
doping on the optical and structural properties of ZnO 
films were investigated in detail.  
 
2. EXPERIMENTAL  
 
In order to prepare pure ZnO and doping films us-
ing chemical vapors deposition(CVD) techniques on 
glass substrates, the deposition material used were 
dissolved in water as follows: The solution (I) (10.8g) 
Zn(CH3COO)2.2H2O was mixed together with solu-
tion(II) (0.699g) AgNO3, the amount of Ag ranged from 
0.08 to 7.7 mol% (i.e. 1–10 wt.%). Then with solution 
(III) (0.721g) PVP. The total amount of used water was 
100 mL. The obtained solution (I+II+III) was placed in 
the heating unit. The pressurized air flow was also ad-
justed to the best flow rate which was found to be 2 
L/min to produce the best samples. Various tempera-
tures were tested when heating the deposition material 
-  C) 
is the appropriate temperature. The substrates were 
first cleaned in acetone, rinsed in deionized water and 
in absolute ethanol, and then placed in the deposition 
unit. While the temperatures were varied between 
(400-500 C) in order to ensure optimum film properties. 
After that prepared ZnO/Ag thin film with various Ag 
concentrations (1,5,10)% to investigate the influence of 
doping on the optical and structural properties. 
The crystalline structure of the as-prepared ZnO/Ag 
films were characterized by X-ray diffraction (XRD) 
with a DX-2700 diffract meter using CuKα radiation 
(λ = 1.54178 nm). The diffraction angle was scanned 
from 20 to 80 at the scanning speed of 0:02±per second. 
The surface  microstructure was obtained by scanning 
electron microscope (SEM) (JEUM-JSM-6756 F) operat-
ing at a voltage of 10 KeV. Optical properties were 
measured through spectrophotometer (ShimadzuUV-
3150). 
 
3. RESULTS AND DISCUSSION 
 
3.1 X-ray diffraction 
 
Figure 1 shows the XRD patterns of ZnO pure and 
 N.Y. JAMIL, S.A. NAJIM, ET AL. PROC. NAP 3, 02NEA09 (2014) 
 
 
02NEA09-2 
ZnO/Ag thin films, which  demonstrate that all the ZnO 
films are crystallized in hexagonal structure. In figure 
1 the XRD pattern of ZnO and ZnO/Ag films recorded 
in the range of 20-80 . X−ray diffraction 
measurements for pure ZnO films and doped showed 
multi crystalline with preferred direction of (101). All 
diffraction peaks (100), (002), (101), (102), (110), (103), 
(112) & (201) can be attributed to  crystalline ZnO with 
the hexagonal structure. The data are in agreement 
with the Joint Committee on Powder Diffraction 
Standards (JCPDS) card for ZnO (JCPDS036-1451) 
[14]. At 1 % Ag doped, We observed that there is one 
peak with low intensity of orientation (111) which due 
to the silver, in addition to the other peaks due to ZnO 
films. But for the ZnO films doped with 5 % Ag 
appeared three new peaks (200) (220) and (311) which 
due to the silver and with increased of the intensity of 
(111) with comparing to the films at 1 % Ag. By 
increasing doping at 10 % Ag, the peak intensity of 
(111) is clearly increased with comparing to 1 % and 
5 % Ag. 
 
 
 
Fig. 1 – XRD pattern of ZnO: Ag with various concentrations 
(0, 1, 5, 10 % Ag) respectively 
 
3.2  EDXA: 
 
EDXA analysis for ZnO doped at 10 % Ag  as shown 
in figure (3) which shows that the dominant composi-
tion of ZnO and the details of the relative analysis are 
depicted in table inside the figure. Fig. 3 shows two 
strong peaks corresponding to Zn which confirms the 
high purity of the ZnO thin films  as well as two strong 
peaks corresponding to Si and O elements and presence 
peaks with low intensity due to Ag, Cu, O and Zn ele-
ments.  
 
 
 
Fig. 2 –  EDXA of ZnO doped at 10 % Ag 
 
3.3 SEM 
 
Scanning electron microscopy (SEM) was used for 
the study of surface morphological changes of pure and 
doped ZnO films prepared by CVD. Figs. (3 a-d) exhibit 
the SEM images of the films ZnO pure and ZnO doped 
at (1, 5, 10 %) Ag respectively. It can be seen that the 
grain size becomes larger by increasing  of doping Ag.  
 
 
 
 
Fig. 3 – SEM of ZnO films a-pure b-1% c-5% d-10% Ag 
 
3.4 Optical properties:  
 
Figure 4 shows the optical transmittance spectra of 
ZnO/Ag thin films in the wavelength range between 
350 to 1550 nm. The transparency properties of all thin 
films are nearly 80-90 % at a visible wavelength of 
(350-800 nm). It is observed that the transmittance has 
a tendency to increase with Ag doped.  
 
 
 
Fig. 4 – Optical transmittance spectra of  ZnO pure and doped 
(1, 5, 10 %) Ag 
 
The relation between absorption coefficient (α) and 
photon energy for direct transitions is given by [15]. 
 
 αhν = A(hν − Eg)/2 (3.1) 
 
where, h is the Plank constant, ν is the frequency of the 
incident photon, A is a constant depending on the elec-
tron-hole mobility and Eg is the optical band gap ener-
gy.  
 
 PREPARATION, STRUCTURAL AND OPTICAL CHARACTERIZATION… PROC. NAP 3, 02NEA09 (2014) 
 
 
02NEA09-3 
 
 
Fig. 5 – Plot of (αhν)2 vs. hν of ZnO pure& doped at (1, 5, 
10 %) Ag 
 
Fig. 5 shows the optical band gap energy versus Au 
doped and it also shows a blue shift in the thin film. By 
extrapolating the linear part of the curve that inter
sects at the x axis, it will give the optical band gap en-
ergy value. For pure ZnO thin film, the band gap ener-
gy found to be 3.25 eV. With an increment in the Ag 
content as 1 %, the band gap nearly increased to 
3.35 eV. This was followed by 3.45 and 3.5 eV for 5 and 
10 % of Ag content, respectively as shown in fig. 5. 
 
4. CONCLUSION 
 
Zinc Oxide thin films doped with Ag using CVD 
technique (0 to 10 % Ag) . the dopping found to lead to 
pronounced changes in their morphology and the band 
gap energy of pure ZnO thin film was 3.25 eV, with the 
increasing of Ag doping it is not affected.  X-ray diffrac-
tion has shown that the maximum intensity peak cor-
responds to the (101) predominant orientation for ZnO 
and ZnO:Ag. SEM images show that more crystalline 
behavior by increasing the doping.  
 
 
REFERENCES 
 
1. A.D. Pogrebnjak, N.Y. Jamil, A.K.M. Muhammed, 
Metallofiz. Noveishie Tekhnol. 33, 235 (2011). 
2. B. Lin, Zh. Fu, Yu. Jia, Appl. Phys. Lett. 79, 943 (2001). 
3. V. Srikant, D.R. Clarke, J. Appl. Phys. 81, 6357 (1997). 
4. T. Minami, H. Nato, S. Takata, Thin Solid Films 124, 43 
(1985). 
5. A.D. Pogrebnjak, N.Y. Jamil, A.K.M. Muhammed, Nano-
mater.: Appl. Prop. 2, 226 (2011).  
6. K.L. Chopra, S. Major, D.K. Panday, Thin Solid Films 
102, 1 (1983)  
7. A.D. Pogrebnjak, A.A. Muhammed, E.T. Karash, 
N.Y. Jamil, J. Partyka, Przegląd Elektrotech. 89, 315 
(2013).  
8. A.D. Pogrebnjak, A.K.M. Muhammed, Visnyk KhNU 962 
No 15, 58 (2011). 
9. J. Hupkes, B. Rech, O. Kluth, T. Repmann, B. Zwaygardt, 
J. Muller, R. Drese, M. Wuttig, Sol. Energ. Mat. Sol. C. 90, 
3054 (2006). 
10. W.J. Jeong, S.K. Kim, G.C. Park, Thin Solid Films 506-
507, 180 (2006). 
11. M. Suchea, S. Christoulakis, K. Moschovis, N. Katsarakis, 
G. Kiriakidis, Thin Solid Films 515, 551 (2006). 
12. W. Water, S.-Y. Chu, Y.-D. Juang, S.-J. Wu, Mater. Lett. 
57, 998 (2002). 
13. F. Michelotti, A. Belardini, A. Rousseau, A. Ratsimihety, 
G. Schoer, J. Mueller, Non-Cryst. Solids 352, 2339 (2006).  
14. American Society for Testing and Material. Powder Dif-
fraction Files; (Joint Committee on Powder Diffraction 
Standards: Swarthmore, PA, 1999, 3-888). 
15.  R. Azimirad, O. Akhavan, A.Z. Moshfegh, J. Electrochem. 
Soc. E 11-6, 153 (2006).  
 


Preparation, Structural and Optical Characterization of ZnO/Ag Thin Film by CVD

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 3 No 2, 02NEA09(3pp) (2014)   2304-1862/2014/3(2)02NEA09(3) 02NEA09-1  2014 Sumy State University Preparation, Structural and Optical Characterization of ZnO / Ag Thin Film by CVD  N.Y. Jamil1, S.A. Najim1, A.M. Muhammed2, *, V.M. Rogoz2  1 Physics DeP., College of Science, Mosul Univ., Mosul, Iraq 2 Sumy State University, 2, Rimsky-Korsakov Str., 40007 Sumy, Ukraine  (Received 15 July 2014; published online 29 August 2014)  Zinc Oxide thin films doped with Ag have been synthesized by CVD technique. By increasing the dopant from 0 to 10 % Ag in ZnO thin films were found to lead to pronounced changes in their morphology. From optical properties the band gap energy of pure ZnO thin film was 3.25 eV, with the increasing of Ag doping from 1 to 10 % it is not affected. X-ray diffraction has shown that the maximum intensity peak corresponds to the (101) predominant orientation for ZnO and ZnO:Ag. SEM images show that more crystalline behavior by increasing the doping. EDXA analysis showed that the structure of ZnO film contains Zn and O elements and Ag, Cu, Si for doping at 10 % Ag.  Keywords: CVD, X-ray Diffraction, SEM.   PACS number: 62.20.Qp                                                           *kareem19592003@yahoo.co.uk   1. INTRODUCTION  Transparent conducting n-type semiconductor zinc oxide (ZnO) films have been extensively studied in recent year because they exhibit wide band gap [1, 2], optical transmission, electrical conduction and exciton binding energy of 60 meV [2] at room temperature. This exciton binding energy is much larger than the room temperature thermal energy (26 meV), suggesting that the electron-hole pairs are stable even at room temperature. It has crystalline structure of the wurtzite type and with lattice constants a = 3.24 ?, c = 5.19 ? [3]. ZnO thin film is a promising material in the applications of UV light devices, light emitting diodes (LEDs) and laser systems [4], and is used in antireflection coatings, transparent electrodes in solar cells, piezoelectric devices, gas sensors [5], etc. Several techniques were used to prepare ZnO thin films namely: thermal evaporation [6], spray pyrolysis [5-6], RF/DC magnetron sputtering [7], chemical vapour deposition (CVD) methods [5,8], Molecular beam epitaxy [9], pulsed-laser deposition (PLD) [10], chemical bath deposition technique [11], hydrothermal method [12] and sol–gel [13]. Doping is done to control the ZnO physical properties. Usually, n-type doping is obtained by Al, Ag, Ga or In. On the other hand, p-type doping is not easily obtained. However, it is difficult to achieve visible light absorption on a single ZnO material. The silver Ag have been mostly extensively investigated as the important candidate for wide band gap material to absorb light. Ag offer high performance absorption in visible light without any highly toxic elements. Many different methods have been used to prepare Ag–ZnO thin films , RF magnetron sputtering method [8], CVD [5], and so on. However, there are few report on the preparation of Ag–ZnO film on the glass substrate by CVD. It was an important method to synthesize films. The method is cost-effective, simple and can be carried out under low temperature. In this paper, the simple CVD method was used to obtain the ZnO/Ag thin film on the glass substrate. Effects of Ag doping on the optical and structural properties of ZnO films were investigated in detail.   2. EXPERIMENTAL   In order to prepare pure ZnO and doping films us-ing chemical vapors deposition(CVD) techniques on glass substrates, the deposition material used were dissolved in water as follows: The solution (I) (10.8g) Zn(CH3COO)2.2H2O was mixed together with solu-tion(II) (0.699g) AgNO3, the amount of Ag ranged from 0.08 to 7.7 mol% (i.e. 1–10 wt.%). Then with solution (III) (0.721g) PVP. The total amount of used water was 100 mL. The obtained solution (I+II+III) was placed in the heating unit. The pressurized air flow was also ad-justed to the best flow rate which was found to be 2 L/min to produce the best samples. Various tempera-tures were tested when heating the deposition material -  C) is the appropriate temperature. The substrates were first cleaned in acetone, rinsed in deionized water and in absolute ethanol, and then placed in the deposition unit. While the temperatures were varied between (400-500 C) in order to ensure optimum film properties. After that prepared ZnO/Ag thin film with various Ag concentrations (1,5,10)% to investigate the influence of doping on the optical and structural properties. The crystalline structure of the as-prepared ZnO/Ag films were characterized by X-ray diffraction (XRD) with a DX-2700 diffract meter using CuKα radiation (λ = 1.54178 nm). The diffraction angle was scanned from 20 to 80 at the scanning speed of 0:02±per second. The surface  microstructure was obtained by scanning electron microscope (SEM) (JEUM-JSM-6756 F) operat-ing at a voltage of 10 KeV. Optical properties were measured through spectrophotometer (ShimadzuUV-3150).  3. RESULTS AND DISCUSSION  3.1 X-ray diffraction  Figure 1 shows the XRD patterns of ZnO pure and  N.Y. JAMIL, S.A. NAJIM, ET AL. PROC. NAP 3, 02NEA09 (2014)   02NEA09-2 ZnO/Ag thin films, which  demonstrate that all the ZnO films are crystallized in hexagonal structure. In figure 1 the XRD pattern of ZnO and ZnO/Ag films recorded in the range of 20-80 . X−ray diffraction measurements for pure ZnO films and doped showed multi crystalline with preferred direction of (101). All diffraction peaks (100), (002), (101), (102), (110), (103), (112) & (201) can be attributed to  crystalline ZnO with the hexagonal structure. The data are in agreement with the Joint Committee on Powder Diffraction Standards (JCPDS) card for ZnO (JCPDS036-1451) [14]. At 1 % Ag doped, We observed that there is one peak with low intensity of orientation (111) which due to the silver, in addition to the other peaks due to ZnO films. But for the ZnO films doped with 5 % Ag appeared three new peaks (200) (220) and (311) which due to the silver and with increased of the intensity of (111) with comparing to the films at 1 % Ag. By increasing doping at 10 % Ag, the peak intensity of (111) is clearly increased with comparing to 1 % and 5 % Ag.    Fig. 1 – XRD pattern of ZnO: Ag with various concentrations (0, 1, 5, 10 % Ag) respectively  3.2  EDXA:  EDXA analysis for ZnO doped at 10 % Ag  as shown in figure (3) which shows that the dominant composi-tion of ZnO and the details of the relative analysis are depicted in table inside the figure. Fig. 3 shows two strong peaks corresponding to Zn which confirms the high purity of the ZnO thin films  as well as two strong peaks corresponding to Si and O elements and presence peaks with low intensity due to Ag, Cu, O and Zn ele-ments.     Fig. 2 –  EDXA of ZnO doped at 10 % Ag  3.3 SEM  Scanning electron microscopy (SEM) was used for the study of surface morphological changes of pure and doped ZnO films prepared by CVD. Figs. (3 a-d) exhibit the SEM images of the films ZnO pure and ZnO doped at (1, 5, 10 %) Ag respectively. It can be seen that the grain size becomes larger by increasing  of doping Ag.      Fig. 3 – SEM of ZnO films a-pure b-1% c-5% d-10% Ag  3.4 Optical properties:   Figure 4 shows the optical transmittance spectra of ZnO/Ag thin films in the wavelength range between 350 to 1550 nm. The transparency properties of all thin films are nearly 80-90 % at a visible wavelength of (350-800 nm). It is observed that the transmittance has a tendency to increase with Ag doped.     Fig. 4 – Optical transmittance spectra of  ZnO pure and doped (1, 5, 10 %) Ag  The relation between absorption coefficient (α) and photon energy for direct transitions is given by [15].   αhν = A(hν − Eg)/2 (3.1)  where, h is the Plank constant, ν is the frequency of the incident photon, A is a constant depending on the elec-tron-hole mobility and Eg is the optical band gap ener-gy.    PREPARATION, STRUCTURAL AND OPTICAL CHARACTERIZATION… PROC. NAP 3, 02NEA09 (2014)   02NEA09-3   Fig. 5 – Plot of (αhν)2 vs. hν of ZnO pure& doped at (1, 5, 10 %) Ag  Fig. 5 shows the optical band gap energy versus Au doped and it also shows a blue shift in the thin film. By extrapolating the linear part of the curve that intersects at the x axis, it will give the optical band gap en-ergy value. For pure ZnO thin film, the band gap ener-gy found to be 3.25 eV. With an increment in the Ag content as 1 %, the band gap nearly increased to 3.35 eV. This was followed by 3.45 and 3.5 eV for 5 and 10 % of Ag content, respectively as shown in fig. 5.  4. CONCLUSION  Zinc Oxide thin films doped with Ag using CVD technique (0 to 10 % Ag) . the dopping found to lead to pronounced changes in their morphology and the band gap energy of pure ZnO thin film was 3.25 eV, with the increasing of Ag doping it is not affected.  X-ray diffrac-tion has shown that the maximum intensity peak cor-responds to the (101) predominant orientation for ZnO and ZnO:Ag. SEM images show that more crystalline behavior by increasing the doping.    REFERENCES  1. A.D. Pogrebnjak, N.Y. Jamil, A.K.M. Muhammed, Metallofiz. Noveishie Tekhnol. 33, 235 (2011). 2. B. Lin, Zh. Fu, Yu. Jia, Appl. Phys. Lett. 79, 943 (2001). 3. V. Srikant, D.R. Clarke, J. Appl. Phys. 81, 6357 (1997). 4. T. Minami, H. Nato, S. Takata, Thin Solid Films 124, 43 (1985). 5. A.D. Pogrebnjak, N.Y. Jamil, A.K.M. Muhammed, Nano-mater.: Appl. Prop. 2, 226 (2011).  6. K.L. Chopra, S. Major, D.K. Panday, Thin Solid Films 102, 1 (1983)  7. A.D. Pogrebnjak, A.A. Muhammed, E.T. Karash, N.Y. Jamil, J. Partyka, Przegląd Elektrotech. 89, 315 (2013).  8. A.D. Pogrebnjak, A.K.M. Muhammed, Visnyk KhNU 962 No 15, 58 (2011). 9. J. Hupkes, B. Rech, O. Kluth, T. Repmann, B. Zwaygardt, J. Muller, R. Drese, M. Wuttig, Sol. Energ. Mat. Sol. C. 90, 3054 (2006). 10. W.J. Jeong, S.K. Kim, G.C. Park, Thin Solid Films 506-507, 180 (2006). 11. M. Suchea, S. Christoulakis, K. Moschovis, N. Katsarakis, G. Kiriakidis, Thin Solid Films 515, 551 (2006). 12. W. Water, S.-Y. Chu, Y.-D. Juang, S.-J. Wu, Mater. Lett. 57, 998 (2002). 13. F. Michelotti, A. Belardini, A. Rousseau, A. Ratsimihety, G. Schoer, J. Mueller, Non-Cryst. Solids 352, 2339 (2006).  14. American Society for Testing and Material. Powder Dif-fraction Files; (Joint Committee on Powder Diffraction Standards: Swarthmore, PA, 1999, 3-888). 15.  R. Azimirad, O. Akhavan, A.Z. Moshfegh, J. Electrochem. Soc. E 11-6, 153 (2006).   

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Preparation, Structural and Optical Characterization of ZnO/Ag Thin Film by CVD

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