We report on the epitaxial growth of superconducting molybdenum films on sapphire substrates. These films are to be etched into arrays of isolated cylinders, each 1–5μm in diameter. When placed in a magnetic field and biased at 0.95 Tc(H), the flux movement associated with their bolometric response to the energy deposited when radiation is absorbed will provide the basis of a gamma-ray detector.
The films were prepared by UHV sputter deposition at temperatures between 650° and 840°C. Besides standard XRD analysis the films were examined by TEM. An epitaxy orientation relationship with sapphire was found similar to that observed for niobium. Electrical conductivity measurements were made as a function of temperature down to Tc, the superconducting transition temperature, which ranged from below 0.35K to above 0.8K for films with a high room temperature resistance ratio (e.g. 300 in a 0.9pjn thick film). Results from a range of films will be presented and their Tc’s discussed.