The possibility of growing high-quality $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{e}}_3$ thin films is crucial to exploring the properties of topological surface states. Since sputtering is a well-established growth technique and it can be used on an industrial scale, the study of sputtered $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{e}}_3$ thin film represents a path for direct large-scale device production. This work presents a systematic study of RF-sputtered growth of $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{e}}_3$ thin film at room temperature on (100)-oriented MgO substrates. The structural and chemical properties of $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{e}}_3$ thin films are characterized by high-resolution transmission electron microscopy (HRTEM); in-depth energy dispersion x-ray spectroscopy; x-ray photoemission spectroscopy (XPS); x-ray diffraction (XRD); x-ray reflectivity (XRR); and Raman spectroscopy techniques, which confirm the growth of high-quality and stoichiometric compounds. Atomic force microscopy (AFM) and scanning tunneling microscopy (STM) reveal films characterized by granular surface morphology. Scanning tunneling spectroscopy (STS), a technique that measures the local density of states (LDOS) of the surface, confirms the presence of surface states. The STS maps show that the Dirac point shifts as we approach a grain boundary.

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• Topological insulators