Influence of Copper Oxide Top Layer on Structural and Optical Properties of Tin Sulfide Thin Films Deposited by Spray Pyrolysis

Abstract

In this work, the effect of the upper cupric oxide (CuO) layers by spray pyrolysis on the optical and structural characteristics of tin sulfide (SnS) thin films was investigate. The SnS film displays dual phases of orthorhombic and Zincblende and the appearance of a monoclinic CuO phase after the deposition of the upper layer. The field emission scanning electron microscopy (FE-SEM) reveals notable variations in surface characteristics after deposition of the top layer. The general increase in optical absorbance with no alterations in the optical bandgap (2 eV) was demonstrated. The photoluminescence test (PL) shows the characteristic emission peaks at 485nm (2.55eV) attributed to S vacancies and lattice defects and 550nm (2.25eV) band-to-band transitions. Additional PL peaks corresponding to the CuO structure were observed at 395nm (3.14eV) for the double-layered samples. The results indicate that modifying the optical and structural characteristics of CuO/SnS heterostructures makes them suitable for use in numerous applications.