Accessing new 2D semiconductors with optical band gap: synthesis of iron-intercalated titanium diselenide thin films LPCVD.

Fe-doped TiSe thin-films were synthesized low pressure chemical vapor deposition (LPCVD) of a single source precursor: [Fe(η-CHSe)Ti(η-CH)] (1). Samples were heated at 1000 °C for 1-18 h and cooled to room temperature following two different protocols, which promoted the formation of different phases. The resulting films were analyzed by grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and UV/vis spectroscopy. An investigation of the Fe doping limit from a parallel pyrolysis study of Fe TiSe powders produced during LPCVD depositions has shown an increase in the Fe-TiSe-Fe layer width with Fe at% increase. Powders were analyzed using powder X-ray diffraction (PXRD) involving Rietveld refinement and XPS. UV/vis measurements of the semiconducting thin films show a shift in band gap with iron doping from 0.1 eV (TiSe) to 1.46 eV (FeTiSe).