A novel selenization technique for fabrication of superconducting FeSex thin film

A combinative method with reactive sputtering deposition and selenization technique was applied to prepare superconducting FeSex films on LaAlO3 substrates successfully. The influence of selenizing temperature on film components was studied. FeSe0.96 and FeSe films had similar and good performances in transport measurement but little difference in magnetic property. The critical onset temperature got to 11.2 K and Tc,0 got to 4 K approximately. X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy were used to analyze the ratio of constituents and morphology of several selenized films. FeSex film had a porous structure on surface and no well preferred orientation, which were confirmed to have little influence on superconducting properties.

► A novel selenization technique was applied to prepare superconducting FeSex films with pre-set FeS films.
► The combination of reactive sputtering deposition with elemental diffusion technique would extend to prepare films of other iron-based superconductors.
► The results of transport measurement got close or greater than that of previous reports. Tc,onset and Tc,0 got to 10.2 K and 4 K respectively.
► We believe that increase of the content of Fe7Se8 could not only reduce Tc but also slow down the decline of resistivity.