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

Fe-doped TiSe 2 thin-films were synthesized via low pressure chemical vapor deposition (LPCVD) of a single source precursor: [Fe(η 5 -C 5 H 4 Se) 2 Ti(η 5 -C 5 H 5 ) 2 ] 2 (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 x TiSe 2 powders produced in situ during LPCVD depositions has shown an increase in the Fe-TiSe 2 -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 2 ) to 1.46 eV (Fe 0.46 TiSe 2 ).