# I. INTRODUCTION onsiderable attention has been paid for the last few decades to the binary compounds based on the Sn-S system, due to their excellent properties and the high potential use in optoelectronic devices [1][2][3][4]. In particular tin disulfide (SnS 2 ) was considered as one of very interesting tin sulfides semiconductors. SnS 2 has been known for its potential applications in solar cells as well as electrical switchings [5]. Also SnS 2 belongs to IV-VI group of semiconductor compound with hexagonal crystal structure (a= 0.3648 nm, c= 0.5899 nm) [6]. It has a wide band gap energy (2.88 eV) [7], and n-type electrical conductivity with magnitude depending on the preparation methods. Thin films of SnS 2 compound has been prepared by different technologies deposition techniques. Such as, chemical bath deposition [8], vacuum thermal evaporation [9], close-spaced sublimation [10], successive ionic layer adsorption and reaction (SILAR) [11], spray pyrolysis [12]. In this paper we report a chemical method called ultrasonic spray, for the deposition of SnS 2 thin films at 330 °C onto ordinary glass substrates. The effect of molar concentration parameter on the films properties and their characterization by X-ray diffraction, chemical analysis, and optical techniques are also reported. Author ? ? ? ? : Laboratoire des Semi-conducteurs, Département de Physique, Faculté des Sciences, Université Badji-Mokhtar, BP 12, Annaba, DZ-23000, Algérie. e-mail: kenza_kamli@yahoo.fr II. EXPERIMENTAL DETAILS Tin disulfide thin films were prepared by spraying an alcoholic solution containing tin chloride IV (SnCl 4 (2H 2 O)) and thiourea CS(NH 2 ) 2 on glass substrates using spray pyrolysis process. Substrates were degreased in successive rinses with acetone, ethanol, and distilled water. Then, the total solution was sprayed during 25 min on heated substrates at 330 °C. A set of samples was obtained by changing the precursor molar concentration from 0,05 to 0,08 mol/l in atmospheric pressure. The films were characterized by means of structural, morphological, and optical methods. The X ray diffraction studies were carried out using a D8 ADVANCED BRUKER diffractometer using a Cu K? radiation (?=1.5405 Å) in range of 10-85°, the crystallite size were estimated to study the effect of the molar concentration. The surface morphology of the films was observed using a JEOL, model JSM 6301F Scanning Microscopy by field effect. The surface morphological studies were done with the SEM photographs taken with JEOL model JSM6400 scanning microscope. To have an idea about the surface elemental composition of the film, energy dispersive analysis by X-rays (EDAX) was carried out using EDX spectrometer related to the SEM used before. # III. RESULTS AND DISCUSSION # a) Structural characteristics The XRD profile of the ultrasonic sprayed SnS 2 thin films on glass substrates is shown in Fig. 1. The prominent Bragg reflection occurring at about 2? ? 15.14° along with many other weak peaks confirms the polycrystalline nature of the films. In all cases we found that (001) is the preferred orientation, so we can say that all SnS 2 thin films are in hexagonal crystallographic phase (JCPDS 23-0677), with the c-axis perpendicular to the substrate. The average crystallite sizes of the films deposited with different molarities have been calculated using the Scherrer's formula: Where ?, ? and ? are X-ray wavelength, the Bragg's diffraction angle and the full width at half maxima of the peak corresponding to the ? value, respectively. Crystallite size for samples obtained with different concentrations is shown in fig. 2. It can be observed that the grain size decreased with the molar concentration increasing of sprayed precursor solution from 13.93 nm to 9.5 nm. # b) Morphological characteristics The Fig. 3 shows typical SEM images and EDAX spectra of films deposited with the four studied solution concentrations and at substrate temperature 330 °C taken as example. Microscopic examination reveals that the obtained deposits are uniform and compact with good coverage to the substrate basis. As can be seen, the films morphology depends strongly on the concentration solution of the used precursor. Film deposited at 0.08 mol/l has a continuous and dense structure with a very smooth surface morphology as reveals Fig. 3.d. The EDX spectra of the SnS 2 films recorded in Fig. 3 shows the atomic and weight percentages of the elements present in the films and assure the chemical composition of SnS 2 . As can be seen, atomic ratio for the samples increases with concentration solution increasing. Also it can be noted, that the formed film at 0.08 mol/l contain S and Sn with almost 39% and 61% ratio, respectively, which is the most near stoichiometric ratio for SnS 2 composition. In addition the presence of Cl is due to the used precursor, and those of O, N is due to the air. # c) Optical characteristics Fig. 4 shows the optical transmittance curves as a function of the wavelength for the SnS 2 films deposited at 330°C with different molar concentrations. As can be seen the optical transmittance increase with the molarity increasing. The fall of transmittance between 300 nm and 400 nm shows that the films absorb the light ultra violet. Furthermore, film deposited at 0.08 mol/l exhibits interference fringe in the transmittance spectrum and a high transparency than the other films. This is due to the smooth surface of the former. It is well known that rough surface causes the light scattering resulting in transmittance reduction. This explains the low transmittance measured in films deposited with the lowest molar concentration. # IV. CONCLUSIONS In the present work we have studied the influence of solution properties on SnS 2 thin films deposition by spray pyrolysis. Four molar concentrations were investigated. X-ray diffraction analysis reveals a polycrystalline nature (hexagonal phase) for all the films deposited at Ts = 330 °C. It was observed that the grain size is varied between ~ 14 and 9.5 nm. The morphological studies using SEM showed that the films are uniform and compact with good coverage to the substrate basis. EDS results confirm the presence of Sn and S. The optical characterization showed that the films transparent increase with molar concentration increasing. From these values we have suggested that the film deposited at 0.08 mol/l can be a potential candidate as an optical window in solar cells. # References Références Referencias Elaboration of Sns 2 Thin Films by Ultrasonic Spray for Solar Cell Application 1![Fig. 1: X-ray diffraction pattern of SnS 2 thin films with different molar concentrations.](image-2.png "Fig. 1 :") 2![Fig. 2: Variation of crystallite size with different concentrations of solution.](image-3.png "Fig. 2 :") 3![Fig. 3: SEM images and EDX spectra of SnS 2 thin films deposited at substrate temperature equal to 330 °C with different solutions concentration: (a) 0.05 mol/l (b) 0.06 mol/l (b) 0.07 mol/l and (c) 0.08 mol/l.](image-4.png "Fig. 3 :") 4![Fig. 4: UV-visible transmittance spectrum of SnS 2 thin films deposited at 330 °C using different solutions molar concentration: (a) 0.05 mol/l (b) 0.06 mol/l (b) 0.07 mol/l and (c) 0.08 mol/l.](image-5.png "Fig. 4 :") ![Journals Inc. (US) Global Journal of Researches in Engineering ( ) Volume XVII Issue V Version I](image-6.png "") © 2017 Global Journals Inc. (US) * GValiukonics DAGuseinova GKrivaite ASileica Phys. Status Solidi, B Basic Res 135 299 1990 * MT SNair PKFair J. Phys. D: Appl. Phys 24 83 1991 * AOrtiz JCAlonso MGarc?´a JToriz Semicond. Sci. Technol 11 243 1996 * SLo ´pez AOrtiz Semicond. Sci. Technol 9 1 1994 * RBissessur DSchipper Materials Letters 62 2008 * AChakrabarti JLu AMMcnamara LMKuta SMStanley ZXiao JAMaguire NSHosmane Inorganica Chimica Acta 374 2011 * FTan SQu XZeng CZhang MShi ZWang LJin YBi JCao ZWang YHou FTeng ZFeng Solid State Communications 150 2010 * KTRamakrishna Reddy GSreedevi KRamya RWMiles Energy Procedia 15 2012 * ChengwuShi ZhuChen GaoyangShi RenjieSun XiaopingZhan XinjieShen Thin Solid Films 520 2012 * ChengwuShi PengfeiYang MinYao XiaoyanDai Zhu ChenThin, Solid Films 534 2013 * NGDeshpande AASagade YGGudage CDLokhande RamphalSharma Journal of Alloys and Compounds 436 2007 * OAYassin AAAbdelaziz AYJaber Materials Science in Semiconductor Processing 38 2015