Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern
technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis
technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as
source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition, morphological and optical properties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with
(111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate temperature.
The optical properties of these films have been studied in the wavelength range 300-2500 nm using
UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV

Adnane, M.

Djelloul, A.

Larbah, Y.

Maha, A.

Rahal, B.

Sahraoui, T.

Zegadi, C.

Electronic Sumy State University Institutional Repository

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ Vol. 7 No 4, 04045(5pp) (2015) Том 7 № 4, 04045(5cc) (2015)   2077-6772/2015/7(4)04045(5) 04045-1  2015 Sumy State University Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method  A. Djelloul1,2,*, M. Adnane1, Y. Larbah1, T. Sahraoui1, C. Zegadi1, A. Maha2, B. Rahal3  1 Laboratory of Electron Microscopy and Materials Sciences University of Science and Technology of Oran,  B.P. 1505, 31000 El-Mnaouer Oran, Algeria 2 Centre de Recherche en Technologie des Semi-Conducteurs pour l’Energétique ‘CRTSE’  02 Bd Frantz Fanon. B.P. 140, 7 Merveilles, Alger, Algérie 3 Nuclear Research Center of Algiers (CRNA), 2 Bd., Frantz Fanon, BP 399, Algiers 16000, Algeria   (Received 07 October 2015; published online 10 December 2015)  Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the in-fluence of substrate temperature on the structure, chemical composition, morphological and optical proper-ties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with (111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate tempera-ture. The optical properties of these films have been studied in the wavelength range 300-2500 nm using UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV.  Keywords: ZnS, Spray Pyrolysis, DRX, UV-VIS, Band gap.   PACS numbers: 81.05.Dz, 78.66.Hf, 61.05.Cp, 78.66. – Hf                                                                   * djelloulcrtse@gmail.com 1. INTRODUCTION  Zinc sulphide belongs to II-VI group compound ma-terial with large direct band gap  3.50 eV depending upon composition. Zinc sulphide (ZnS) is an important semiconducting material with a wide direct band gap and n-type conductivity is promising for optoelectronic device applications, such as electroluminescent devices and photovoltaic cells [1-4]. Several techniques on growing ZnS thin films have been reported, which in-clude Spray Pyrolysis (SP) [5, 6], Successive Ionic Lay-er Adsorption and Reaction (SILAR) [7-10], RF sputter-ing [11], Chemical Bath Deposition (CBD) [12-18], Molecular Beam Epitaxy (MBE) [19], Dip Technique (DT), Pulsed-Laser Deposition (PLD) [20], Chemical Vapour Deposition (CVD) [21]. In present investigation ZnS thin films have been deposited using Chemical Spray Pyrolysis techniques. The morphological, structural and optical properties of the as deposited ZnS thin films were studied.  2. EXPERIMENTAL DETAILS  2.1 Materials and Methods  Thin films of ZnS are prepared by Spray Pyrolysis technique. Spray Pyrolysis is basically a Chemical deposition technique in which fine droplets of the de-sired material solution was sprayed onto a heated sub-strate. The experimental Setup used for the prepara-tion of pyrolytically spray deposited films is described here. The initial solution was prepared with one part of 0.1 M ZnCl2 and one part 0.1 M SC(NH2)2 [thiourea] in deionzed water. The deposition temperature was 300 °C-400 °C, the distance between the substrate and the spray gun nozzle was fixed at 35 cm. A schematic drawn of the spray pyrolysis apparatus for the synthe-sis of the ZnS particles is depicted in Figure 1. The morphological, optical, structural and compositional analysis of films has been investigated by SEM, UV spectroscopy; XRD and EDAX.  3. CHARACTERIZATIONS  The surface morphologies of films were examined by electronic microscopy (SEM) (JEOL, (JSM-6610LA)). The structural characterization of the films was ana-lyzed using X-ray diffractometer (XRD) (Siemens D500) with Cu Kα radiation. The Fourier Transform Infrared (FTIR) spectra of the samples were recorded using JAS-CO FI-IR 460 spectrometer by KBr pellet technique in the range 400-4000 cm – 1. The resistivity of the samples     Fig. 1 – Schematic diagram of spray pyrolysis process of ZnS preparation  A. DJELLOUL, M. ADNANE, ET AL. J. NANO- ELECTRON. PHYS. 7, 04045 (2015)   04045-2 and the gas sensing was measured using a two-point probe conventional instrument. The optical transmit-tance measurements of the films were performed with a UV-Visible spectrophotometer (Cary 500).  4. RESULTS AND DISCUSSION  4.1 Morphological Properties  The scanning electron microscopy technique is fa-miliar for the study of surface morphology of metal chalcogenides in the thin film form. The ZnS film pre-pared with optimized parameters is used for SEM ob-servation. SEM images of ZnS thin films deposited on glass substrate at different substrate temperatures (Ts  300-400 °C) are shown in Fig. 2 (a, b and c). The surface of the thin films displays an inhomoge-neous appearance in all scanned areas of the sample as shown in Fig. 2.        Fig. 2 – Scanning Electron microscopy as deposited ZnS on glass substrate at: 300 °C sprayed (a), 350 °C sprayed (b) and 400 °C sprayed (c)  4.2 Structural Properties  The X-ray diffraction pattern of ZnS films is also reported in the present work with the help of a Philip X-ray diffractometer by using CuKα radiation (  1.54045 Å). The average grain size was calculated from the Scherrer formula, which involve the width of the X-ray diffraction line [22].   cosKD   (1)  Where: D is the mean particle size.  is the full width at half maximum (FWHM in ra-dians) of the peak corrected for instrumental broaden-ing, and θ is the diffraction / Bragg’s angle.  is the wavelength of the X-ray radiation (0.15406 nm). K: is the Scherer constant, it is value is taken as 0.9 for the calculations [23-25]. The grain size of ZnS thin films were found to be about 25 nm and 60 nm. X-ray diffraction profiles of ZnS thin films prepared at various substrate temperatures (Ts  300-400 °C) are shown in Fig. 3 (a, b and c). One can note the progres-sive emergence of the diffraction peak located at 28° underlining a strong preferential orientation growth perpendicular to the crystallographic plans (111), which corresponds to ZnS cubic structure [26]. The intensity of the peak is enhanced with increasing the substrate temperature; it becomes intense when the substrate temperature is equal to 400 °C. In Fig. 4, a typical EDX spectrum for ZnS film is in-dicated. The films used in this analysis are deposited at substrate temperature, 400 °C. As can be seen, films are composed of S and Zn. According to XRD diffraction results (Fig. 3 (a) and (b)), films deposited at low temperature have an amor-phous structure, since no peaks is present in the XRD diffraction pattern, or at least it is composed with a small crystallite size. The Fourier transform infrared (FTIR) measure-ments were undertaken to confirm the formation of the thin films. Fig. 5 (a) and (b) shows the FTIR spectra of    а b а c  PROPERTIES STUDY OF ZNS THIN FILMS… J. NANO- ELECTRON. PHYS. 7, 04045 (2015)   04045-3     Fig. 3 – X-ray diffraction pattern of sprayed ZnS film at substrate temperature: 350 °C (a), 350 °C (b) and 400 °C (c)    Fig. 4 – SEM micrograph spectrum analysis and EDAX of ZnS thin film at substrate temperature, 400 °C ZnS thin film at substrate temperature, 350 °C and at 400 °C respectively. It can be seen that each sample shows a weak characteristic vibrations of zinc sulfide located at 611.45 and 680 cm – 1, others peaks are at-tributed to the formation of ZnS nanoparticles.     Fig. 5 – FTIR Spectrum of ZnS thin film at substrate tempera-ture, 350 °C (a) and 400 °C (b)  4.3 Optical Properties  Optical transmission and reflection for the ZnS thin films on glass substrates were measured in the range (300-2500 nm) using a spectrophotometer. The spectral transmittance curves of these films are shown in Fig. 6.    Fig. 6 – Optical transmission and reflection spectra of ZnS thin films prepared at various substrate temperatures (Ts  350 °C and 400 °C) b b а c  A. DJELLOUL, M. ADNANE, ET AL. J. NANO- ELECTRON. PHYS. 7, 04045 (2015)   04045-4 Fig. 6 shows the transmittance of ZnS films pre-pared at various substrate temperatures (Ts  350 °C and 400 °C). As can be seen, an increase in the sub-strate temperature improves the films optical trans-mission. It passes from 50 % to 90 % at the incident wavelength of 600 nm. Generally, the film transmit-tance is increased with the reduction of film thickness. However, in our case, the transmittance improvement cannot be explained in terms of films thickness, since with increasing the substrate temperature films became thick-er (the thickness is varied from 120 nm to 245 nm with increasing temperature).Thereafter, the transmittance improvement may originates from the film structure. The optical energy gap for the direct allowed transi-tion between valence bands and conduction bands of ZnS thin films was calculated from equation (2) using r  1/2.      rghv A h E    (2)      Fig. 7 – The optical energy gap of ZnS thin films prepared: a) at substrate temperature (Ts  350 °C), b) at substrate tem-perature (Ts  400 °C)  ZnS is a direct band gap material; several workers reported this type of transition. The energy gaps of the films of various substrate temperatures have been determined by extrapolating the linear portion of the plots of  2hv  against hv  (eV) to the energy axis. The band gap value was determined from the inter-cept of the straight-line portion of the  2hv  against the graph on the hv  axis (see Fig. 7). The band gap energies are calculated to be between 3.89-3.96 eV for the ZnS films with different substrate temperatures. The wide direct band gap makes these films good material for potential applications in optoe-lectronic devices such as multilayer dielectric filters, and solar cell due to decreases the window absorption loses and that will improves the short circuit current of the cell.  5. CONCLUSION  Chemical spray pyrolysis method was used success-fully to synthesize ZnS thin films from a double-source precursor at substrate temperatures of 300, 350, and 400 °C. Studies on morphological, structural and opti-cal properties were performed on the samples using scanning election microscope (SEM), X-ray diffraction (XRD), Energy Dispersive X-ray analysis (EDAX), Fou-rier Transform Infrared Spectroscopy (FTIR), and UV-VIS spectrophotometer (UVS). We noted that film structure composition and opti-cal properties are very sensitive to the deposition tem-perature. At low deposition temperature films are amorphous. With increasing Ts, the films became poly-crystalline with (111) preferential orientation with a stoichiometric ZnS composition. EDAX and FTIR data confirm the formation of ZnS nanoparticles. In our experiment, based on the optical transmission meas-urements, the band gap energies are calculated to be between 3.89-3.96 eV for the ZnS films with different thicknesses. The optical studies also revealed band gap dependence on substrate temperatures. The wide ener-gy band gap Eg  3.50 and high transmittance make the ZnS film suitable for solar cell and opto-electronic applications.  ACKNOWLEDGMENTS  This work was supported by all members of Labora-tory of Electron Microscopy and Materials Sciences University of Science and Technology of Oran and Cen-tre de Recherche en Technologie des Semi-Conducteurs pour l’Energétique ‘CRTSE’, Algeria. The authors would like to thank Algerian Ministry of Higher Educa-tion and Scientific Research and Directorate General for Scientific Research and Technological Development.   а b  PROPERTIES STUDY OF ZNS THIN FILMS… J. NANO- ELECTRON. PHYS. 7, 04045 (2015)   04045-5  REFERENCES  1. S. Yamaga, A. Yoshokawa, H. Kasain, J. Cryst. Growth 86, 252 (1998). 2. I.C. Ndukwe, Sol. Energ. Mater. Sol. C. 40, 123 (1996). 3. T.E. Varitimos, R.W. Tustison, Thin Solid Films 151, 27 (1987). 4. J. Vidal, O. de Melo, O. Vigil, N. Lopez, G. Contreras-Puente, O. Zelaya-Angel, Thin Solid Films 419, 118 (2002). 5. H.L. Kwok, J. Phys. D: Appl. Phys. 16, 2367 (1983). 6. O.M. Hussain, P.S. Reddy, B.S. Naidu, U. Uthanna, P.J. Reddy, Semicond. Sci. Technol. 6, 690 (1991). 7. M.P. Valkonen, S. Lindroos, T. Kanniainen, M. Leskela, U. Tapper, E. Kauppinen, Appl. Surf. Sci. 120, 58 (1997). 8. Y.F. Nicolau, J.C. Menard, J. Crystal Growth 92, 128 (1988). 9. G. Xu, S. Ji, C. Miao, G. Liu, C. Ye, J. Mater. Chem. 22, 4890 (2012). 10. H.M. Pathan, C.D. Lokhande, Bull. Mater. Sci. 27, 85 (2004). 11. L-X. Shaoi, K-H. Chang, H-L. Hwang, Appl. Surf. Sci. 212, 213 (2003). 12. H. Lekiket, M.S. Aida, Mater. Sci. Semicond. Proc. 16, 1753 (2013). 13. P. Roy, J.R. Ota, S.K. Srivastava, Thin Solid Films 515, 1912 (2006). 14. T. BenNasr, N. Kamoun, M. Kanzari, R. Bennaceur, Thin Solid Films 500, 4 (2006). 15. F. Gōde, C. Gümüs, M. Zor, J. Cryst. Growth 299, 136 (2007). 16. G.L. Agawane, S.W. Shin, A.V. Moholkar, K.V. Gurav, J.H. Yun, J.Y. Lee, J.H. Kim, J. Alloy. Compd. 535, 53 (2012). 17. T. Lwushita, S.Z. Shi, Thin Solid Films 520, 7076 (2012). 18. Z.Q. Li, J.H. Shi, Q.Q. Liu, Z.A. Wang, Z. Sun, S.M.  Huang, Appl. Surf. Sci. 257, 676 (2010). 19. K. Ichino, T. Onishi, Y. Kawakami, S. Fujita. J. Crystal Growth 138, 28 (1994). 20. Z.J. Xin, R.J. Peaty, H.N. Rutt, R.W. Eason, Semicond. Sci. Technol. 14, 695 (1999). 21. T.L. Chu, S.S. Chu, J. Britt, C. Feredikes, C.Q. Wu,  J. Appl. Phys. 70, 2688 (1991). 22. S. Lindroos, G. Rusu, J. Optoelectron. Adv. Mater. 7, 817 (2005). 23. S.S. Nath, D. Chakdar, G. Gope, Nanotrends- A journal of nanotechnology and its application 02, 03 (2007). 24. S.S. Nath, D. Chakdar, G. Gope, D.K. Avasthi, J. Nanoe-lectron. Optoelectron. 3, 180 (2008). 25. B.D. Hall, D. Zanchet, D. Ugarte, J. Appl. Crystallography 33, 1335 (2000). 26. Ali A. Yousif, Aseel A. Jasib, Int. J. Innovative Sci., Engin. Technol. 2 No 3, 886 (2015).  

Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method

SocioEconomic Challenges Journal (Sumy State University)

JOURNAL OF NANO- AND ELECTRONIC PHYSICS ЖУРНАЛ НАНО- ТА ЕЛЕКТРОННОЇ ФІЗИКИ 
Vol. 7 No 4, 04045(5pp) (2015) Том 7 № 4, 04045(5cc) (2015) 
 
 
2077-6772/2015/7(4)04045(5) 04045-1  2015 Sumy State University 
Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method 
 
A. Djelloul1,2,*, M. Adnane1, Y. Larbah1, T. Sahraoui1, C. Zegadi1, A. Maha2, B. Rahal3 
 
1 Laboratory of Electron Microscopy and Materials Sciences University of Science and Technology of Oran,  
B.P. 1505, 31000 El-Mnaouer Oran, Algeria 
2 Centre de Recherche en Technologie des Semi-Conducteurs pour l’Energétique ‘CRTSE’  
02 Bd Frantz Fanon. B.P. 140, 7 Merveilles, Alger, Algérie 
3 Nuclear Research Center of Algiers (CRNA), 2 Bd., Frantz Fanon, BP 399, Algiers 16000, Algeria 
 
 (Received 07 October 2015; published online 10 December 2015) 
 
Zinc sulfide (ZnS) is important II-VI semiconductors material for the development of various modern 
technologies and photovoltaic applications. ZnS thin film was prepared by using chemical spray pyrolysis 
technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as 
source of S. The glass substrate temperature was varied in the range of 300 °C-400 °C to investigate the in-
fluence of substrate temperature on the structure, chemical composition, morphological and optical proper-
ties of ZnS films. The DRX analyses indicated that ZnS films have polycrystalline cubic structure with 
(111) preferential orientation and grain size varied from 25 to 60 nm, increasing with substrate tempera-
ture. The optical properties of these films have been studied in the wavelength range 300-2500 nm using 
UV-VIS spectro-photometer. The ZnS films has a band gap of 3.89 eV-3.96 eV. 
 
Keywords: ZnS, Spray Pyrolysis, DRX, UV-VIS, Band gap. 
 
 PACS numbers: 81.05.Dz, 78.66.Hf, 61.05.Cp, 
78.66. – Hf 
 
 
                                                                
* djelloulcrtse@gmail.com 
1. INTRODUCTION 
 
Zinc sulphide belongs to II-VI group compound ma-
terial with large direct band gap  3.50 eV depending 
upon composition. Zinc sulphide (ZnS) is an important 
semiconducting material with a wide direct band gap 
and n-type conductivity is promising for optoelectronic 
device applications, such as electroluminescent devices 
and photovoltaic cells [1-4]. Several techniques on 
growing ZnS thin films have been reported, which in-
clude Spray Pyrolysis (SP) [5, 6], Successive Ionic Lay-
er Adsorption and Reaction (SILAR) [7-10], RF sputter-
ing [11], Chemical Bath Deposition (CBD) [12-18], 
Molecular Beam Epitaxy (MBE) [19], Dip Technique 
(DT), Pulsed-Laser Deposition (PLD) [20], Chemical 
Vapour Deposition (CVD) [21]. 
In present investigation ZnS thin films have been 
deposited using Chemical Spray Pyrolysis techniques. 
The morphological, structural and optical properties of 
the as deposited ZnS thin films were studied. 
 
2. EXPERIMENTAL DETAILS 
 
2.1 Materials and Methods 
 
Thin films of ZnS are prepared by Spray Pyrolysis 
technique. Spray Pyrolysis is basically a Chemical 
deposition technique in which fine droplets of the de-
sired material solution was sprayed onto a heated sub-
strate. The experimental Setup used for the prepara-
tion of pyrolytically spray deposited films is described 
here. The initial solution was prepared with one part of 
0.1 M ZnCl2 and one part 0.1 M SC(NH2)2 [thiourea] in 
deionzed water. The deposition temperature was 
300 °C-400 °C, the distance between the substrate and 
the spray gun nozzle was fixed at 35 cm. A schematic 
drawn of the spray pyrolysis apparatus for the synthe-
sis of the ZnS particles is depicted in Figure 1. The 
morphological, optical, structural and compositional 
analysis of films has been investigated by SEM, UV 
spectroscopy; XRD and EDAX. 
 
3. CHARACTERIZATIONS 
 
The surface morphologies of films were examined by 
electronic microscopy (SEM) (JEOL, (JSM-6610LA)). 
The structural characterization of the films was ana-
lyzed using X-ray diffractometer (XRD) (Siemens D500) 
with Cu Kα radiation. The Fourier Transform Infrared 
(FTIR) spectra of the samples were recorded using JAS-
CO FI-IR 460 spectrometer by KBr pellet technique in 
the range 400-4000 cm – 1. The resistivity of the samples  
 
 
 
Fig. 1 – Schematic diagram of spray pyrolysis process of ZnS 
preparation 
 A. DJELLOUL, M. ADNANE, ET AL. J. NANO- ELECTRON. PHYS. 7, 04045 (2015) 
 
 
04045-2 
and the gas sensing was measured using a two-point 
probe conventional instrument. The optical transmit-
tance measurements of the films were performed with 
a UV-Visible spectrophotometer (Cary 500). 
 
4. RESULTS AND DISCUSSION 
 
4.1 Morphological Properties 
 
The scanning electron microscopy technique is fa-
miliar for the study of surface morphology of metal 
chalcogenides in the thin film form. The ZnS film pre-
pared with optimized parameters is used for SEM ob-
servation. SEM images of ZnS thin films deposited on 
glass substrate at different substrate temperatures 
(Ts  300-400 °C) are shown in Fig. 2 (a, b and c). 
The surface of the thin films displays an inhomoge-
neous appearance in all scanned areas of the sample as 
shown in Fig. 2. 
 
 
 
 
 
 
 
Fig. 2 – Scanning Electron microscopy as deposited ZnS on glass 
substrate at: 300 °C sprayed (a), 350 °C sprayed (b) and 400 °C 
sprayed (c) 
 
4.2 Structural Properties 
 
The X-ray diffraction pattern of ZnS films is also 
reported in the present work with the help of a Philip 
X-ray diffractometer by using CuKα radiation 
(  1.54045 Å). 
The average grain size was calculated from the 
Scherrer formula, which involve the width of the X-ray 
diffraction line [22]. 
 
 
cos
K
D

 
  (1) 
 
Where: 
D is the mean particle size. 
 is the full width at half maximum (FWHM in ra-
dians) of the peak corrected for instrumental broaden-
ing, and θ is the diffraction / Bragg’s angle. 
 is the wavelength of the X-ray radiation 
(0.15406 nm). K: is the Scherer constant, it is value is 
taken as 0.9 for the calculations [23-25]. 
The grain size of ZnS thin films were found to be 
about 25 nm and 60 nm. 
X-ray diffraction profiles of ZnS thin films prepared 
at various substrate temperatures (Ts  300-400 °C) are 
shown in Fig. 3 (a, b and c). One can note the progres-
sive emergence of the diffraction peak located at 28° 
underlining a strong preferential orientation growth 
perpendicular to the crystallographic plans (111), 
which corresponds to ZnS cubic structure [26]. The 
intensity of the peak is enhanced with increasing the 
substrate temperature; it becomes intense when the 
substrate temperature is equal to 400 °C. 
In Fig. 4, a typical EDX spectrum for ZnS film is in-
dicated. The films used in this analysis are deposited at 
substrate temperature, 400 °C. As can be seen, films are 
composed of S and Zn. 
According to XRD diffraction results (Fig. 3 (a) and 
(b)), films deposited at low temperature have an amor-
phous structure, since no peaks is present in the XRD 
diffraction pattern, or at least it is composed with a 
small crystallite size. 
The Fourier transform infrared (FTIR) measure-
ments were undertaken to confirm the formation of the 
thin films. Fig. 5 (a) and (b) shows the FTIR spectra of  
 
 
а 
b 
а 
c 
 PROPERTIES STUDY OF ZNS THIN FILMS… J. NANO- ELECTRON. PHYS. 7, 04045 (2015) 
 
 
04045-3 
 
 
 
 
Fig. 3 – X-ray diffraction pattern of sprayed ZnS film at substrate 
temperature: 350 °C (a), 350 °C (b) and 400 °C (c) 
 
 
 
Fig. 4 – SEM micrograph spectrum analysis and EDAX of ZnS 
thin film at substrate temperature, 400 °C 
ZnS thin film at substrate temperature, 350 °C and 
at 400 °C respectively. It can be seen that each sample 
shows a weak characteristic vibrations of zinc sulfide 
located at 611.45 and 680 cm – 1, others peaks are at-
tributed to the formation of ZnS nanoparticles. 
 
 
 
 
Fig. 5 – FTIR Spectrum of ZnS thin film at substrate tempera-
ture, 350 °C (a) and 400 °C (b) 
 
4.3 Optical Properties 
 
Optical transmission and reflection for the ZnS thin 
films on glass substrates were measured in the range 
(300-2500 nm) using a spectrophotometer. The spectral 
transmittance curves of these films are shown in Fig. 6. 
 
 
 
Fig. 6 – Optical transmission and reflection spectra of ZnS thin 
films prepared at various substrate temperatures (Ts  350 °C 
and 400 °C) 
b 
b 
а 
c 
 A. DJELLOUL, M. ADNANE, ET AL. J. NANO- ELECTRON. PHYS. 7, 04045 (2015) 
 
 
04045-4 
Fig. 6 shows the transmittance of ZnS films pre-
pared at various substrate temperatures (Ts  350 °C 
and 400 °C). As can be seen, an increase in the sub-
strate temperature improves the films optical trans-
mission. It passes from 50 % to 90 % at the incident 
wavelength of 600 nm. Generally, the film transmit-
tance is increased with the reduction of film thickness. 
However, in our case, the transmittance improvement 
cannot be explained in terms of films thickness, since with 
increasing the substrate temperature films became thick-
er (the thickness is varied from 120 nm to 245 nm with 
increasing temperature).Thereafter, the transmittance 
improvement may originates from the film structure. 
The optical energy gap for the direct allowed transi-
tion between valence bands and conduction bands of 
ZnS thin films was calculated from equation (2) using 
r  1/2. 
 
    
r
ghv A h E    (2) 
 
 
 
 
 
Fig. 7 – The optical energy gap of ZnS thin films prepared: a) 
at substrate temperature (Ts  350 °C), b) at substrate tem-
perature (Ts  400 °C) 
 
ZnS is a direct band gap material; several workers 
reported this type of transition. The energy gaps of the 
films of various substrate temperatures have been 
determined by extrapolating the linear portion of the 
plots of  
2
hv  against hv  (eV) to the energy axis. 
The band gap value was determined from the inter-
cept of the straight-line portion of the  
2
hv  against 
the graph on the hv  axis (see Fig. 7). 
The band gap energies are calculated to be between 
3.89-3.96 eV for the ZnS films with different substrate 
temperatures. The wide direct band gap makes these 
films good material for potential applications in optoe-
lectronic devices such as multilayer dielectric filters, 
and solar cell due to decreases the window absorption 
loses and that will improves the short circuit current of 
the cell. 
 
5. CONCLUSION 
 
Chemical spray pyrolysis method was used success-
fully to synthesize ZnS thin films from a double-source 
precursor at substrate temperatures of 300, 350, and 
400 °C. Studies on morphological, structural and opti-
cal properties were performed on the samples using 
scanning election microscope (SEM), X-ray diffraction 
(XRD), Energy Dispersive X-ray analysis (EDAX), Fou-
rier Transform Infrared Spectroscopy (FTIR), and UV-
VIS spectrophotometer (UVS). 
We noted that film structure composition and opti-
cal properties are very sensitive to the deposition tem-
perature. At low deposition temperature films are 
amorphous. With increasing Ts, the films became poly-
crystalline with (111) preferential orientation with a 
stoichiometric ZnS composition. EDAX and FTIR data 
confirm the formation of ZnS nanoparticles. In our 
experiment, based on the optical transmission meas-
urements, the band gap energies are calculated to be 
between 3.89-3.96 eV for the ZnS films with different 
thicknesses. The optical studies also revealed band gap 
dependence on substrate temperatures. The wide ener-
gy band gap Eg  3.50 and high transmittance make 
the ZnS film suitable for solar cell and opto-electronic 
applications. 
 
ACKNOWLEDGMENTS 
 
This work was supported by all members of Labora-
tory of Electron Microscopy and Materials Sciences 
University of Science and Technology of Oran and Cen-
tre de Recherche en Technologie des Semi-Conducteurs 
pour l’Energétique ‘CRTSE’, Algeria. The authors 
would like to thank Algerian Ministry of Higher Educa-
tion and Scientific Research and Directorate General 
for Scientific Research and Technological Development. 
 
 
а 
b 
 PROPERTIES STUDY OF ZNS THIN FILMS… J. NANO- ELECTRON. PHYS. 7, 04045 (2015) 
 
 
04045-5 
 
REFERENCES 
 
1. S. Yamaga, A. Yoshokawa, H. Kasain, J. Cryst. Growth 86, 
252 (1998). 
2. I.C. Ndukwe, Sol. Energ. Mater. Sol. C. 40, 123 (1996). 
3. T.E. Varitimos, R.W. Tustison, Thin Solid Films 151, 27 
(1987). 
4. J. Vidal, O. de Melo, O. Vigil, N. Lopez, G. Contreras-
Puente, O. Zelaya-Angel, Thin Solid Films 419, 118 
(2002). 
5. H.L. Kwok, J. Phys. D: Appl. Phys. 16, 2367 (1983). 
6. O.M. Hussain, P.S. Reddy, B.S. Naidu, U. Uthanna, 
P.J. Reddy, Semicond. Sci. Technol. 6, 690 (1991). 
7. M.P. Valkonen, S. Lindroos, T. Kanniainen, M. Leskela, 
U. Tapper, E. Kauppinen, Appl. Surf. Sci. 120, 58 (1997). 
8. Y.F. Nicolau, J.C. Menard, J. Crystal Growth 92, 128 
(1988). 
9. G. Xu, S. Ji, C. Miao, G. Liu, C. Ye, J. Mater. Chem. 22, 
4890 (2012). 
10. H.M. Pathan, C.D. Lokhande, Bull. Mater. Sci. 27, 85 
(2004). 
11. L-X. Shaoi, K-H. Chang, H-L. Hwang, Appl. Surf. Sci. 212, 
213 (2003). 
12. H. Lekiket, M.S. Aida, Mater. Sci. Semicond. Proc. 16, 
1753 (2013). 
13. P. Roy, J.R. Ota, S.K. Srivastava, Thin Solid Films 515, 
1912 (2006). 
14. T. BenNasr, N. Kamoun, M. Kanzari, R. Bennaceur, Thin 
Solid Films 500, 4 (2006). 
15. F. Gōde, C. Gümüs, M. Zor, J. Cryst. Growth 299, 136 
(2007). 
16. G.L. Agawane, S.W. Shin, A.V. Moholkar, K.V. Gurav, 
J.H. Yun, J.Y. Lee, J.H. Kim, J. Alloy. Compd. 535, 53 
(2012). 
17. T. Lwushita, S.Z. Shi, Thin Solid Films 520, 7076 (2012). 
18. Z.Q. Li, J.H. Shi, Q.Q. Liu, Z.A. Wang, Z. Sun, S.M.  
Huang, Appl. Surf. Sci. 257, 676 (2010). 
19. K. Ichino, T. Onishi, Y. Kawakami, S. Fujita. J. Crystal 
Growth 138, 28 (1994). 
20. Z.J. Xin, R.J. Peaty, H.N. Rutt, R.W. Eason, Semicond. 
Sci. Technol. 14, 695 (1999). 
21. T.L. Chu, S.S. Chu, J. Britt, C. Feredikes, C.Q. Wu,  
J. Appl. Phys. 70, 2688 (1991). 
22. S. Lindroos, G. Rusu, J. Optoelectron. Adv. Mater. 7, 817 
(2005). 
23. S.S. Nath, D. Chakdar, G. Gope, Nanotrends- A journal of 
nanotechnology and its application 02, 03 (2007). 
24. S.S. Nath, D. Chakdar, G. Gope, D.K. Avasthi, J. Nanoe-
lectron. Optoelectron. 3, 180 (2008). 
25. B.D. Hall, D. Zanchet, D. Ugarte, J. Appl. Crystallography 
33, 1335 (2000). 
26. Ali A. Yousif, Aseel A. Jasib, Int. J. Innovative Sci., Engin. 
Technol. 2 No 3, 886 (2015). 
 


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https://essuir.sumdu.edu.ua/bitstream/123456789/43254/1/Djelloul_Properties%20Study%20of%20ZnS_.pdf

Properties Study of ZnS Thin Films Prepared by Spray Pyrolysis Method

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