Amorphous Sulfide Heterostructure Precursors Prepared by Radio Frequency Sputtering

Two-dimensional sulfides and their heterostructures have emerged as potentially useful materials for technological applications. Controllable self-assembly of interleaved crystalline heterostructures from designed thin-film precursors has been demonstrated in selenide and telluride chemical systems, but not yet in sulfide chemistries. Preparing such amorphous sulfide heterostructure precursors is a necessary first step toward this goal. Here, deposition of thin-film amorphous precursors for layered sulfide heterostructures by RF sputtering is presented on the example of SnS-MoS₂. A calibration process specific to the mechanisms of RF sputtering from sulfide and disulfide compound targets is established. Precursor film structure and composition are confirmed via X-ray reflectivity and Rutherford backscattering measurements. Local nanostructure and composition are also examined by electron microscopy and electron energy loss spectroscopy.