Electrochemical Preparation And Characterization Of Three-dimensional Nanostructured Tin Sulfides Semiconductor Films With Nanorod Network

The binary tin sulfide semiconductors such as SnS, SnS2 and Sn2S3 have been attracting considerable attention due to their narrow band gaps, which entitle them to the promising applications in photovoltaic devices, near-infrared detectors and optical recording medium.In this research, we got SnS and Sn2S3 semiconductor thin films by potentiostatic electrodeposition from a new acid electrolytic bath. We investigated the effect of potentials, annealed temperatures and deposited substrates on films structure, morphology through XRD, SEM, EDS, Mapping, XPS. Then we got the direct band gaps and semiconductor types of these films from UV-VIS-NIR and Hall test.Sn2S3 and SnS thin films were prepared at-0.80 V and-0.90 V vs. SCE by potentiostatic electrodeposition on Ni substrate respectively. The optimum temperature of heating treatment is 250℃. Comparing the XRD and SEM of Sn2S3 and SnS prepared on Ni and ITO, we know that the thin films prepared on ITO have better morphology, little scale and better Sn/S ratio.Herein, attractively, we got SnS and Sn2S3 films with nanorod structures respectively by potentiostatic electrodeposition, accompanied by annealing in 250℃Ar atmosphere, indeed contributing a simple approach to the fabrication of 1D nanostructural tin sulfides. We investigated the variation of the structure, morphology and photoelectric properties between the as-deposited and annealed films in detail.It is found that the preferred orientation of annealed Sn2S3 thin film has changed and formed a three-dimensional network strcture. The Sn/S ratio of Sn2S3 thin film has changed from 1/1.2 to 1/1.23. Meanwhile, the preferred orientation of SnS thin film has also changed. Its structure changed from nanoparticle to nanorod and Sn/S ratio changed from 1.02/1 to 1.49/1.As-deposited Sn2S3 thin film was p type and its direct band gap was 1.87 eV and annealed Sn2S3 thin film was n type and its direct band gap was 1.65 eV. At the same time, as-deposited SnS thin film was n type and its direct band gap was 1.75 eV and annealed SnS thin film was p type and its direct band gap was 1.54 eV.