Accessing new 2D semiconductors with optical band gap: synthesis of iron-intercalated titanium diselenide thin films via LPCVD
Abstract
Fe-doped TiSe2 thin-films were synthesized via low pressure chemical vapor deposition (LPCVD) of a single source precursor: [Fe((5)-C5H4Se)(2)Ti((5)-C5H5)(2)](2) (1). Samples were heated at 1000 degrees 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 FexTiSe2 powders produced in situ during LPCVD depositions has shown an increase in the Fe-TiSe2-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 (TiSe2) to 1.46 eV (Fe0.46TiSe2).