Photovoltaic ZnO/SnSx heterostructures obtained by “electrochemical deposition-successive ionic layer adsorption and reaction” approach

Abstract

In this work, ZnO/SnS/indium tin oxide (ITO)/glass functional heterostructures have been developed using a combined approach of electrodeposition of a SnSx layer and successive ionic layer adsorption and reaction (SILAR) of the ZnO layer. The high-quality 400 nm-thick orthorhombic SnS0.9–0.95 films were formed on the ITO substrates with a thickness of 130 nm and an electrical conductivity of less than 40 Ω/□. Chemical deposition of ZnO thin films by the SILAR method allowed to deposit hexagonal films with a thickness of about 200 nm. The morphology, elemental and phase composition of the films were characterized by Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The band gap (1.4 eV for SnSx and 3.3 eV for ZnO), as well as the high light absorption coefficient of SnSx films (1–2) × 104 cm–1 were determined. The obtained ZnO/SnSx/ITO heterostructures formed by the electrodeposition–SILAR cycle showed a photoEMF value of 198 mV. These properties make ZnO/SnS heterostructure promising for low-cost solar cells based on affordable materials.