Synthesis and characterization of solution processed p-SnS and n-SnS2 thin films: Effect of starting chemicals

Abstract

This study represents the investigation of earth-abundant and non-toxic SnS absorber and SnS2 buffer layer materials by using a green solution process. Some physical properties of prepared thin films were investigated for different starting chemicals and molar ratios of Sn/S. Here, by using different starting chemicals such as tin (II) 2-ethylhexanoate and tin (II) chloride dihydrate, we observed that the formation of p-SnS and n-SnS2 phases can be simply controlled. All the SnS films obtained by the tin (II) 2-ethylhexanoate showed p-type conductivity. Moreover, it has been observed that an n-type SnS2 thin film can be produced by using tin (II) chloride dihydrate as the starting chemical instead of tin (II) 2-ethylhexanoate. According to the Hall effect measurement results, the resistivity of the p-type films obtained with both starting chemicals is in the order of 106 Ωcm. The resistivity of films with n-type properties drops to the order of 101 Ωcm. The I–V characteristic of the n-SnS2/p-SnS bilayer exhibits the p-n heterojunction diode characteristic. This study paves the way for solution processed SnS and SnS2 thin films as a potential absorber and buffer layer to be used in photovoltaic devices.