Electrical transport properties of ultrathin disordered films

We report an experimental study of quench condensed (2 K ≤ T ≤ 15 K) disordered ultrathin films of Bi where localization effects and superconductivity compete. Experiments are done with different substrates and/or different underlayers. Quasi-free-standing films of Bi, prepared by quenching Bi vapours onto solid Xe, are also studied. The results show a dependence of the transport properties both on the dielectric constant of the substrate/underlayer as well as the temperature of quench condensation. RHEED studies indicate that quantum size effects are important in these systems. In this paper, we try to correlate the structure of the films to the transport properties obtained.