Modification of optical and electrical properties of chemical bath deposited SnS using O2 plasma treatments

In this paper, we report modifications of structural and optical, electrical properties that occur in tin sulphide (SnS) treated in O2 plasma. The SnS thin films were deposited by chemical bath deposition technique. The samples were treated in an O2 plasma discharge at 3 Torr of pressure discharge, a discharge voltage of 2.5 kV and 20 mA of discharge current. The prepared and treated thin films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The photoconductivity and electrical effects of SnS have been studied. The SnS thin films had an orthorhombic crystalline structure. With the plasma treatment the optical gap and electrical properties of the SnS films changed from 1.61 to 1.84 eV, for 3.9 × 105 to 10.42 Ω cm, respectively. These changes can be attributed to an increase in electron density, percolation effects due to porosity, surface degradation/etching that is an increase in surface roughness, where some structural changes related to crystallinity occurs like a high grain size as revealed by SEM images.

► O2 plasma treatment was used to improve the electrical properties of the SnS film. ► Optical band gap of the SnS films were modified by O2 plasma treatment. ► The time treatment has an influence on the electrical properties of films. ► The time treatment has an influence on the optical properties of films. ► SnS is a potential solar cell absorber material.