  Disorder driven superconductor to insulator transition via intermediate
metallic regime is reported in nano-crystalline thin films of molybdenum. The
nano-structured thin films have been deposited at room temperature using DC
magnetron sputtering at different argon pressures. The grain size has been
tuned using deposition pressure as the sole control parameter. A variation of
particle sizes, room temperature resistivity and superconducting transition has
been studied as a function of deposition pressure. The nano-crystalline
molybdenum thin films are found to have large carrier concentration but very
low mobility and electronic mean free path. Hall and conductivity measurements
have been used to understand the effect of disorder on the carrier density and
mobilities. Ioffe-Regel parameter is shown to correlate with the continuous
metal-insulator transition in our samples.
