WSe2 is an earth-abundant semiconductor of interest for application as a photovoltaic absorber due to its high absorption coefficient, phase stability, and a direct bandgap of 1.2-1.5 eV that matches well for optimum absorption by photovoltaic cells. The solvothermal preparation method eliminates the need for expensive high-vacuum fabrication steps but the as-made nanoparticles do not exhibit a sufficient degree of crystallinity or specific crystalline face orientation be cast as suitable thin films for photovoltaic devices. We have successfully fabricated phase-pure WSe2 thin films, as characterized by Raman spectroscopy and x-ray diffraction, via the annealing of either nanocrystalline WSe2 or a tungsten-selenium precursor material that was solvothermally prepared from W(CO)6 and elemental selenium in an aromatic solvent. Materials were annealed in a homemade physical vapor deposition apparatus in an argon atmosphere. The annealing process significantly improved the crystallinity of as-made WSe2 and successfully converted tungsten-selenium precursor material to WSe2 films that were highly (002) face-oriented.

Formation of WSe2 thin films via annealing of a solvothermally prepared nanocrystalline precursor

249th National Meeting (2015)

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