International Journal of Current Engineering and Technology E-ISSN 2277 – 4106, P-ISSN 2347 – 5161 ©2015 INPRESSCO ® , All Rights Reserved Available at http://inpressco.com/category/ijcet Research Article 910| International Journal of Current Engineering and Technology, Vol.5, No.2 (April 2015) Structural Morphology and Electrical Properties of Vacuum Evaporated SnS Thin Films Bushra A.Hasan † and Eman M. Nasir †* † University of Baghdad, College of science, Physics Department, Baghdad, Iraq Accepted 22 March 2015, Available online 29 March 2015, Vol.5, No.2 (April 2015) Abstract Using thermal evaporation technique tin Sulphide (SnS) thin films have been deposited on glass slides have been deposited at room temperature using SnS powder. The deposited films have been investigated through X- ray diffraction measurements to determine structural properties. The deposited SnS films found polycrystalline with an orthorhombic structure. The grain size found to increase with thickness. The surface morphology of the films has been examined using atomic force microscopy AFM. The chemical compositions of the films have been determined using energy dispersive analysis of x-rays (EDAX). The dielectric properties of SnS thin films deposited with different thickness ȋͷͶͶ,͸ͶͶ,and ͹ͶͶnmȌ are presented in this work. The dielectric permittivity ε and ac conductivity σ ac were measured at temperatures in the range of 293–493 K and frequencies in the range of 10 kHz–100MHz. It is found that there are two conductivity mechanisms and hence two activation energies converts to one mechanism with the increase of thickness. The ac activation energy EAC decreases with increase of thickness and frequency. The exponent s shows a progressive decrease with thickness. The results are explained in terms of structural difference by the effect of thickness and thermal treatment. Few anomalies in dielectric studies were observed near 340 and440K, respectively. These points were related to crystalline phase transitions. Dark-conductivity and photo-conductivity increases with increase of thickness. Keywords: SnS semiconductor, XRD, dielectric properties, photoconductivity 1. Introduction 1 Tin sulfide (SnS) is an IV-VI binary semiconductor compound whose constituent elements Tin (Sn) and Sulfur (S) are abundant in nature. SnS in its orthorhombic crystalline structure has direct and indirect band gap values between 1.3–1.5 eV and 1.0– 1.1 eV, respectively and has p-type conductivity. It has higher absorption coefficient (~10 5 cm −1 ) compare to other materials like GaAs and CdTe. These properties make it a better alternative absorber material for photovoltaic applications (J. B. Li et al, 2012; P. P. Choi et al, 2012; J. J. Scragg et al, 2012; L. Grenet et al,2012). SnS thin films have been deposited by different techniques such as: the vacuum evaporation of the SnS compound (L. Price et al, 1999), two stage process (K.T. Ramakrishna et al,2002) and electrochemical deposition (Y. Yamazaki et al, 2003). In this work, thin films of SnS have been grown by thermal evaporation of the prepared bulk material. A description of the methods used for the growth of the SnS films and details of the effect of the deposition parameters on the a.c conductivity properties as well as on the phase and crystalline structure in which the samples grow, will be *Corresponding author: Eman M. Nasir reported. Moreover, we present the activation energy value from the temperature-dependent conductivity measurement. An analysis of the published data indicates that little is known about the a.c conductivity of SnS thin films. Because of this reason, an attempt has been made to deposit SnS thin films with different thicknesses at room temperature in the present work. SnS that have been carried out till date, the experimental results on dielectric study are very few, and that too are very less informative. It is well known that dielectric properties of every solid are very sensitive to the local electric field distribution in the sample. Therefore, the temperature and frequency dependence of dielectric constant and loss can explore useful information about structure changes, transport mechanism and defect behavior. 2. Experimental Description Source material, SnS was prepared by melting high purity elements (99.99%) Sn and S in an evacuated quartz tube at a temperature of 1173 K. Tin sulfide films with different thicknesses (100,200,and 300nm)were deposited on corning 7059 microscopic glass substrate by thermal evaporation technique under high vacuum (10 -5 Torr) at room temperature.