  Superconductivity was recently found in the simple tetragonal FeSe structure.
Recent studies suggest that FeSe is unconventional, with the symmetry of the
superconducting pairing state still under debate. To tackle these problems,
clean single crystals and thin films are required. Here we report the
fabrication of superconducting beta-phase FeSe1-x thin films on different
substrates using a pulsed laser deposition (PLD) technique. Quite
interestingly, the crystal orientation, and thus, superconductivity in these
thin films is sensitive to the growth temperature. At 320C, films grow
preferably along c-axis, but the onset of superconductivity depends on film
thickness. At 500C, films grow along (101), with little thickness dependence.
These results suggest that the low temperature structural deformation
previously found is crucial to the superconductivity of this material.
